Philippine Electrical Wiring – Building our Philippine House

Philippine Electrical Wiring – Building our Philippine House

Wiring your Philippine house.  Philippine electrical wiring.   As part of our project to build our house in the Philippines, we had to learn about Philippine residential electrical systems. Here’s what we’ve learned. As with our other writings, we do our best to chronicle our missteps as well as our successes, so that our readers get slice of reality about coming to the Philippines and building a house, not a fairy tale.  This is not a how-to guide, it’s a description of our experiences.

The transformer serving our house

The transformer serving our house

Our pole-mounted meter

Our pole-mounted meter.  The wires on the left provide power to the meter, the black load wire on the right goes back up the pole and connects to the duplex utility feed or “drop” which connects to the house wiring at the weather head.

From the standpoint of electrical engineering theory, the Philippine system is similar to that used in the U.S. and Europe.  From the utility pole to the residence panel box we have one or two load wires and neutral conductor. We have a ground (earth) provided by the homeowner.   You can explore the technical details at and various other sites.   However there are some big differences in materials and techniques between the USA, Europe, the U.K. and the Philippines. Looking at how things were done when we built our Philippine house may help other considering house building in the Philippines to get an idea how things are done here.  One final note.  The Philippine electricians we have met have been quite professional.  It’s best to hire an electrical engineer to do your plan (you will need it for your building permit), and have good electricians to do the work.  Wage rates are negotiable and far more reasonable than in your home country.  We hope this essay will be of help in making you a more knowledgeable home builder.

First, some background.  Understanding “hot” neutral and ground.  This from Schneider Electric helps explain the purpose and nature of each of the three conductors.

“Electrical power flows in the form of current, which must pass through the equipment and then return to the power source. Therefore, it is convenient to think of one wire to the load being the “source” wire and one being the “return” wire. This simple model is appropriate for DC systems but does not work for an AC system because the flow of the power is continually reversing direction with a frequency of 50 or 60 times per second. From the point of view of the equipment or the power source, the source and return wires are constantly being interchanged. In fact, no equipment can tell which wire is which! It is easily demonstrated that the two power wires to any piece of AC equipment can be interchanged without any effect on function. In fact, in Europe [and the Philippines], the plug on a piece of equipment can be plugged in either way! This fact of symmetry seems to be at odds with the distinct labeling of the AC power wires as “hot” and “neutral”. The reason that one of the power wires is named “neutral” is because it is connected directly to the building ground connection at the circuit breaker panel. Therefore it is connected directly to the grounding (third) wire. In essence, then, two of the three wires at the wall receptacle are actually grounded wires, one being used for power flow, and the other connected only to exposed metal parts on the equipment. The power wire that is grounded is called the “neutral” wire because it is not dangerous with respect to exposed metal parts or plumbing. The “hot” wire gets its name because it is dangerous. The grounding of the neutral wire is not related to the operation of electrical equipment but is required for reasons of safety.” [minor edits]

TYPES OF ELECTRICAL SERVICE IN THE PHILIPPINES. There are two main types of residential electrical service in the Philippines.

MANILA AND CITIES: Three wire 120/240V Systems.  In Manila, Iloilo City and other large Philippine cities, residences are supplied with 240 volt, alternating current, 60 cycle power.  Power from the utility transformer to the residence arrives through three wires, two 120 VAC load (“hot”) wires and a single neutral.  Circuits in the residence are generally wired to supply 240 VAC to outlets using the two 120 VAC load wires, much the same as a heavy appliance (dryer, hot water heater etc.) would be supplied in the U.S. All small and large appliances sold in the Philippines are designed to use 240 VAC, 60C.

However, it is possible to wire in 120 VAC circuits and outlets by using only one of the load wires and a neutral.  These 120 V outlets are seen in hotels, some condos and other places which expect American visitors.   Visitors must keep in mind that the Philippines uses the same style of wall outlets as you see in America, but that the outlet is supplying 240 V, not 120 V.  Plugging a 120 V appliance into a 240 V outlet will generally destroy the appliance.

It seems likely that the American-style 120 / 240  VAC 60 cycle used in Manila may have been the result of the fact that electrical systems in Philippine cities were expanded during the American occupation of the Philippines between 1899 and WWII.  There may be areas around the big former U.S. military bases (Clark and Subic) which are wired for 120 VAC service.

OUTSIDE OF BIG CITIES: Two wire 230V Systems  Areas outside of the old established cities were electrified later and use a different and more economical system using a two wire service drop to the residence.  This consists of one 230 VAC load wire and one neutral wire.  120 VAC cannot be supplied by this type of system unless the property owner, at his own expense and with the cooperation of the utility company, installs his own transformer at the utility pole, a transformer having a secondary winding which can supply 120 VAC.  This is not impossible as many utility transformers are recycled from the U.S., but it is expensive and in our view the 230 V systems are better unless the homeowner ships expensive appliances from the U.S.  It will be difficult to find parts and service for these imported 120 V appliances.

Much of the rest of the world runs on 220-240 VAC but 50 cycle rather than 60 cycle found in the Philippines, creating a problem in importing some European appliances for use in the Philippines.


How can you identify the type of power system you have?  You may look up at the utility feed wires leading from the meter or pole to your house — or a neighbor’s house.  If there are three  wires you probably have two 115 volt load (“hot”) wires and a neutral.  If you have two wires you probably have a single 230 volt load wire and a single combined neutral/ground wire.  With a few exceptions,  Philippine utilities deliver 230 volt, 60 cycle power to your house, but there are differences based on where you live.  Our comments below mostly apply to areas in the Philippines which supply residences using a single 230 volt load wire and a neutral wire to your residence.  They are not fully applicable to urban areas using two 110 volt load wires (including Manila) or to systems around former American military bases.

For our purposes let’s call the three wire urban systems as “three wire 120/240V systems” and the two wire systems as “two wire 230V systems”.

Our residence is located in a rural location served by an electrical cooperative so we have a 230V two wire electrical supply.

Duplex cable from meter to weather head

Duplex cable from meter to weather head

Here is a photo of the point where the utility company service drop or cable  joins with our house wiring at the weather head and enters the house.

The utility feed cables on the right are from the pole, one black load wire and one un-insulated neutral wire.  The black and green feed wires on the left go into our attic and through conduit to our panel box. Again, from the fact that there is only one load wire, we can guess that we have a two wire 230 v. system.  If you had seen two black wires and a neutral leading from the pole to the house, you’re probably dealing with a three wire 120/240V system.

The meter-to-house wire is referred to as “duplex cable”.  If it was three wire it would be referred to as “triplex”.  Our duplex feed cable is a #6 AWG load wire which is insulated and wound with an un-insulated neutral wire.  Both are aluminum.  We had to pay for the duplex wire extending from the meter to our house. We paid about P17 per meter for this cable at Western Lamp, an electrical supply house in Iloilo City. The utility may provide the wire and/or the meter and bill you for it monthly until it’s paid for.  You’ll pay more this way.

Also note that the utility feed is aluminum whereas the panel feed wire is copper.  The two have to be spliced together at the weather head.  Ideally this is done with a special compression splice and splicing tool because copper and aluminum have a different coefficient of expansion, plus the two materials are subject to electrochemical reaction.   One reader commented that he  “found a supplier on Alibaba that sells bimetal AL-Cu crimp connectors  that seem ideal for connecting Al power lines to Cu home drops. They will even sell one piece according to their listing… I’m planning to order a couple of samples for use in my upcoming home building project “…

Splice crimping tool

Splice crimping tool

While the default service drop is the 6AWG aluminum cable, we recently replaced ours with 4AWG aluminum cable to better accommodate a new 2HP air conditioner. Remember that all resistance losses from the meter are paid by the homeowner. We paid about P30 per meter for each strand of the 4AWG cable. We were happy to tear out and replace the old 6AWG wire which had several splices with heavier cable all connected with crimp connectors. The total cost for replacing the 60 meters of service drop was P3,000. If there are any electrical engineers out there, they could calculate the difference in resistance losses between the larger and smaller service drops. Readers have pointed out that since we were splicing aluminum to copper, bimetallic crimps should have been used.

Replacing thin 6AWG drop cable with 4AWG

Replacing thin 6AWG drop cable with 4AWG

At the bottom of each electrical pole is (or should be) a ground rod which is connected to the transformer and to the line serving your house. These provide a ground to the system, but it’s critical to have your own separate ground to ensure that your own neutral wiring is properly grounded.  The utility’s ground is to make their system work.  The home owner’s ground is to protect the household and its wiring system from electrical hazards.

Ground rod at pole

Ground rod at pole

Many Americans considering a move to the Philippines want to know if they can get 120 volt power in the Philippines and whether or not they should bring their 120 volt appliances with them.  If your residence has the two-wire 230 volt system, 120 volts is not going to be available except by means of a step-down transformer inside the house.  Step down transformers generate heat and waste power, but are quite popular in the Philippines and available in almost all hardware stores.

There is no right answer to the question about bringing appliances from the U.S. to the Philippines.  Items used only infrequently, say a food processor or sewing machine, it might make sense to bring. We would not bring Items in constant use, such as a refrigerator.   We have seen Filipinos using 120v power tools, dragging around a step-down transformer.  Bob sold his power tools before leaving the U.S. and bought new ones in the Philippines.  Just remember that electrical plugs in the U.S. and the Philippines look the same, but the first time you plug your 120v gadget into a 230v circuit, will likely be the end of that item.

Foreigners from places other than the U.S. may have an easier time but, even if their appliances are made for 230v use, have to investigate the compatibility of 50 cycle appliances when used on 60 cycle Philippine circuits.

Step-down transformer

Step-down transformer.  It plugs into a 230 volt receptacle and provides 120 volt power

Some expats have bought and installed their own power pole transformers and have been able to get 120v that way. This is an expensive option, possibly more expensive than buying new 230v appliances.

We have seen above that the utility drop cable attaches to the house wiring at the weather head.  Now to follow the wiring from this point to the panel or circuit breaker box.

Our electrical engineer originally proposed a 125 amp panel box for our house.  He probably did this because he was designing for a foreigner who would have hot water and air conditioning throughout and every conceivable electrical appliance and gadget.  We went to the engineer and informed him of our plans and he agreed to a 100 amp panel box using #2 AWG wire.  Even with a 100 amp panel box, at 230 volts we have an almost 25KW capacity, far in excess of any load we can possibly use.

In the Philippines, metric sizing is replacing the AWG (American Wire Gauge) system.  Our #2 AWG cable is designated as 30mm sq., under the metric system. This cable is expensive.   Undersized cable is often used.  Our electricians were astounded that we were using such heavy cable in a residence.  To run the main feed into the attic we used 1″ galvanized pipe.  It should have been 32mm or 1¼”.  There are charts available which specify the required size of conduit. Cable overcrowded in conduit can overheat.

Running the entrance cable in the attic

Running the entrance cable in the attic

The main feed cable has come into the attic through the weather head.  In this photo, the workers are feeding the wire through plastic conduit.  The main feed cable does not go directly to the panel box.  It first goes to a switch allowing the panel box to be supplied by the electrical utility or, in the event of a power failure, by a backup generator.  This switch ensures that no power from the generator can flow into the utility lines, placing utility workers at risk.  It also allows us to put the switch in a neutral position where no power from either source is flowing to the panel box.  This allows us to safely work on the panel box without having the utility company remove the meter.


This photo shows the double-pole, double throw switch which switches between utility company power and power from our generator.  The capacity of the switch is 100 amps.  It cost about $80.  Our generator hookup is the simplest and cheapest kind.  Power from our utility comes in at the top of the switch.  Power from the generator (when running) comes in at the bottom.  The middle terminals connect to the panel box.   Normally, utility power flows through the DPDT switch to the panel box.  During a blackout, the switch is changed to the lower position and the generator is started.  With this simple set-up, power from the generator flows to all circuits.  Because the capacity of the generator is limited, less than what’s available from the utility company, we check to see that high consumption circuits (mostly air conditioning) are not on when we start the generator.  After the generator is running, we have used one of our air conditioners powered by the generator without a problem.

There are more complex switching systems which automatically determine which circuits will be active when the generator is being used.  There are also systems in which the generator automatically starts and automatically switches over when a blackout occurs.  An automatic system would improve security at times when power goes out at night and one has the choice of going outside in the middle of the night to start the generator or to stay inside a dark house, hoping the security lights, air conditioners and fans will come back on soon.

Subpanel for generator

Subpanel for generator

Above is a snapshot of a generator switch which uses a separate circuit and breaker for circuits which are energized when the generator is running.  Also the knife switch is in a box, a good idea!

We did install battery operated emergency lights to illuminate our front porch and garage during power outages.

PANEL BOXES.  The knife switch normally delivers utility power to the main buses of the panel box via #2 AWG (30mm²) cable.  This brings us to a discussion about panel boxes.  Panel (circuit breaker boxes) boxes vary in quality, the number of circuits they can handle, the type of breakers they use and so forth.  We are far from being panel box experts, but we will share our experiences.

If you buy your panel box and breakers in a hardware store you’ll generally find cheaper brands such as Koten, Meiji, Royu and so forth.  We also saw crude copies of GE breakers labeled as “American”.  Some of the panel boxes at hardware stores even had aluminum buses.  It should be noted that these brands are not necessarily cheaper than GE brand breakers sold at specialized electrical supply stores.

If you go to an electrical supply outfit which caters to electricians, you find a wider range of products with better quality and lower prices.  The counter staff at these places can be quite knowledgeable.  Two good places in Iloilo City are Western Lamp and Eastman Electric.  Always ask for a discount, especially if you are buying in quantity.

Bolt on breaker

Bolt on breaker

Plug in breaker showing panel box copper bus bars

Plug in breaker showing panel box copper bus bars

We bought a good quality twenty-circuit panel box with a sturdy copper buses for about P4,100 at Western Lamp in Iloilo City. This box uses GE-style plug-in breakers.  We were offered a choice between a panel box using plug-in or bolt-on breakers.  We chose plug-in because that’s what we were familiar with in the U.S.  As we will see, that was a mistake.

This type of panel box is really engineered for use with the 120-240v three wire type of system but can be used with the 230v three wire systems too.  In a 120-240v three wire system, the two main buses each carry 120v. The buses on the plug-in panel boxes have a zig-zag type of arrangement which works well if your two buses are hot and you have separate neutral and ground busses – such as in the U.S. or in Manila or other Philippine cities.  When you plug in a single-pole breaker you connect to one bus and end up with a 120v circuit.  If you use a double-pole breaker you connect to both buses and get a 240v circuit.

However, if you have a 230v two wire supply, you will use one of the buses as a load bus and the other as a neutral bus.  This works fine except that you have to carefully check the polarity of your circuits to be sure the neutral wires always connect with the neutral bus.  The zig-zag or staggered  buses mean that the order of the load and neutral buses are reversed on the left and right buses.

Diagram of panel box with staggered bus

Diagram of panel box with staggered bus

The maximum capacity of the plug in breakers is 100 amps, so if you need a panel box with a larger capacity, buy one designed for bolt-on breakers.  Further, in Iloilo City single-pole breakers are not available in the plug-in style.  We strongly recommend a panel box with bolt on breakers.

Here is when we got into trouble.  We decided to use single-pole breakers.  We only had one load wire.  What was the point in “protecting” the neutral side of the circuit, we asked ourselves?  It’s a general rule that neutral lines should not be switched or fused.  So, we bonded the two panel box busses together and made them both hot with 230v.  We would use single pole breakers protecting the load wires and tie the neutrals to a separate neutral bus.  This simultaneously converted our twenty breaker double pole box to a forty circuit single-pole box.  Brilliant!

bus with captions

Not really.  Since we found that single pole breakers were not available for our plug-in panel box, we looked at double pole breakers and they seemed to be two single pole breakers tied together.  We cut the links on the handles and wired up our panel box.  Everything seemed to work just fine.

Panel box wired single pole

Panel box wired single pole.  Note that only the right bus was used.

Gradually, we learned that circuit breakers are much more complicated than we thought.  Breakers provide protection for both instantaneous large surges in current (short circuit) and lower, longer term overages from an overloaded circuit.

Inside a circuit breaker (Wikipedia)

Inside a circuit breaker (Wikipedia) This is a European DIN mount breaker.

  1. Actuator lever – used to manually trip and reset the circuit breaker. Also indicates the status of the circuit breaker (On or Off/tripped). Most breakers are designed so they can still trip even if the lever is held or locked in the “on” position. This is sometimes referred to as “free trip” or “positive trip” operation.
  2. Actuator mechanism – forces the contacts together or apart.
  3. Contacts – Allow current when touching and break the current when moved apart.
  4. Terminals
  5. Bimetallic strip.
  6. Calibration screw – allows the manufacturer to precisely adjust the trip current of the device after assembly.
  7. Solenoid
  8. Arc divider/extinguisher

The assumption that the two halves of DP breakers can serve as SP breakers proved to be very wrong.  The double-pole breakers are NOT just two single pole breakers physically joined.  We found this out the hard way when we had a total short in one of our circuits and the 20 amp breaker did not trip, but instead melted a #12 AWG wire.  This must have been a huge overload, far beyond 20 amps.

We then tested the breakers on a test circuit.  We found that only one side of our double pole breaker provide short circuit protection. It’s unknown which side may provide over current protection.  Presumably, breakers made to be used as single-pole provide both protections in a single breaker, as do double-pole breakers used as a unit.

We decided we were not so smart after all. Since we had a plug-in type of panel box for which single-pole breakers are not available, we had no choice but to wire our plug-in style panel box, as many local electricians do, using double-pole breakers.

We took out the link we had installed connecting the two panel box bus bars and bought new double-pole breakers.   Now, one of the buses was hot, the other bus was neutral. When a double pole breaker is installed, one pole of the breaker protects the load wire and one the neutral wire for each branch circuit.

We used a specific GE double pole breaker which is sold and in almost universal use here – the TQL2415X or TQL2420X. Our electrical supply store only sells GE brand breakers. I could not find these “X-suffix” breakers in the huge online GE breaker directory, but did read elsewhere that the X designation is for “special purpose” applications.  The GE breakers sold here are 240/415 volt rated.


Almost all U.S. residential single pole breakers are made for circuits with 120v loads.  The breakers for the U.S. are generally rated at 120-240v.  The GE breakers sold in the Philippines are 240/415 volt rated (see photo above). There may also be internal design differences between the breakers used in the U.S. and in the Philippines which might affect the safety and effectiveness of your system. Breaker engineering is way beyond our comprehension.  We feel it’s best to buy product designed for the local market and electrical systems.

Therefore, we do not recommend bringing breakers from the U.S. The part numbers of the locally sold GE breakers are not the same and we are not certain if they are designed to work properly with 230v two wire systems.  Perhaps, after being burned (literally!) experimenting with breakers, we were not in a mood for further experiments.

We have not seen Siemens or Square D or C-H breakers.  Perhaps they are available in Manila?  The GE double pole breakers we used cost P400  each – after negotiation.  Single-pole GE breakers are available for bolt-in panel boxes.  These should work fine on a panel box made for them but, as we have said, we have decided to follow local wiring customs after our earlier misadventure and given the fact that we had already installed a plug-in type panel box.

Panel Box

Panel Box wired using double pole breakers, one pole load, one pole neutral.

OUR RECOMMENDATION: We live in an area where electricians are called on to install both 230 volt two-wire systems and 240 volt three-wire systems.  On the three wire systems, the electricians must install a panel box using double-pole breakers.  On the two wire systems they can use either single or double-pole breakers.  We feel we were right in the first place in thinking that single pole breakers are a good (and more economical)  choice to the 230 volt two wire systems. What is the point on spending more to install double pole breakers?  Unfortunately, we bought and installed a plug-in style panel box and ended up with no choice but to use double pole breakers.  Starting from scratch, we feel the best option for the 230V two-wire systems is a good bolt-on panel box using genuine GE single-pole bolt-on breakers.

GROUNDING.  One last, but important part of panel box installation is proper grounding.  While the neutral line may be (or may not be) grounded at the base of the utility pole, it is essential that the residence have its own grounding system.  This can be in the form of grounding pipes or rods.  The Philippine 230v two wire system is called a multi-ground system because it depends on a distribution ground provided by the utility company and a protective ground at each panel box.

Rather than using a grounding rod pounded into the soil, we attached brass “acorn” clamps to the rebar in one of the house’s main columns. This rebar leads underground to a mass of rebar in the base of the footer and ultimately to all of the rebar and concrete of the house.  A #6 AWG copper conductor runs from the clamp to the panel box.  Rebar grounding is permitted by both the PEC and NEC.   One advantage of the rebar ground being in the attic is that it is protected from the corrosion or damage risk outdoor ground rods are prone to.

Grounding clamp on rebar in attic

Grounding clamp on rebar in attic

See comments below why some feel rebar does not make a good protective ground.

Most Philippine houses are not wired with three-prong, grounded outlets.  Most outlets have only a load wire and a neutral wire. The quality of grounding of the neutral wire can be uncertain due to improper earthing at the pole or in the residence.  If you’ve spent any time in the Philippines, you’ve probably been repeatedly shocked by your computer, refrigerator and so forth.   The metal parts of these appliances either have no ground (earth) connection and/or the neutral is not properly grounded. When you touch them with bare feet on a tile, you become the ground.  Since bare feet on tile are a pleasure of Philippine retirement, this is best avoided.

Sometimes proper polarity is not maintained in the wiring.  Make sure the neutral (white) wires in branch circuits are attached to the neutral bus in the panel box.  Otherwise the metal parts of an appliance may be connected to a hot wire rather than a neutral.

Unfortunately, it is typical for appliances sold in the Philippines to lack a grounding prong on the plug.  The rusty plug shown above not only does not have a grounding lug, the blades are identical, so that it can be plugged in without regard to the polarity of the outlet.  Generally, outlets have one wider slot and one narrow slot so that plugs can only be plugged in in one way.  This is to ensure that the polarity of the appliance connection is correct, that the neutral rather than hot wire is attached to the metal case of the appliance.

Fortunately, grounded outlets are readily available and that’s what we used.  We ran a separate #14 AWG ground wire to each outlet.  This wire connects to the ground bus in the panel box and from there to our earthing system.  The neutral and ground are bonded in the panel box and only in the panel box.  This neutral to ground bonding is a must.  See Mike Holt’s discussion at


Appliance cord with unpolarized plug and ground lead

 We hardly ever see grounded three prong plugs on appliances sold in the Philippines.  That’s because few houses have grounded outlets.  Sometimes you’ll get a two prong plug with a separate ground wire that the homeowner is left to connect — or not. We suspect that a very small percentage of these are ever connected.  For that reason, the ground wire is more of a fig leaf than a real solution.  Generally we have found that if the neutral wire is well grounded (earthed), these shocks are less common.  Still, it’s best to use these ground wires to prevent serious shocks in case of a failure which connects the hot wire to the metal parts of the appliance.  These grounding leads should always go to a ground (earth) not a neutral.  The best approach may be to cut the original 2-prong plug off of the appliance cord and install a grounded plug, making sure that the polarity is correct.


Even if the neutral and hot wires are correctly connected, a shock hazard still exists unless exterior metal parts of the appliance are not grounded via a separate ground wire.  Above is a photo of a pretty old brass fixture.  Although the polarity of the two conductors is correct, you will get a vicious shock if you touch this lamp because one of the load wires is frayed and touches the brass case.  The barefoot retiree on a tile floor makes an excellent ground!  If this lamp had the metal parts connected to a grounded outlet, the breaker or GFI would trip.

Since the panel box only came with a load and neutral buses, we added a ground (earth) bus.  We were able to buy a very nice brass ground bus to add to the panel box.  The green ground wire from every circuit is connected to this ground bus.

A ground bus in a panel box

An added ground bus in a panel box.  The 2 #10 AWG wires bond the ground bar to incoming neutral utility conductor at the knife switch.

GROUND FAULT INTERRUPTER CIRCUITS (GFI) also called Residual Current Devices (RCD). GFI protection in mandatory in much of the world but is expensive and not often seen in the Philippines, despite the fact that electrical shocks and electrocution are a common events here.  We’ll write more about this later as we add GFI protection to our system.  In the meantime, keep in mind that ordinary circuit breakers are not intended to protect humans from many of the most common types of shock hazards.   A properly operating breaker is intended to carry loads without tripping, loads which could easily electrocute a human being. Consider, for example, that (depending on the design of the breaker)  a 30 A breaker will take one hour to trip at a current of 40 A.   Circuit breakers protect circuits, GFI devices are designed to sense faults and trip fast enough to prevent fatal shocks.

BRANCH CIRCUITS FOR OUTLETS AND LIGHTS.  Now we can discuss wiring “branch” circuits.  Our house plan called for four lighting circuits, eight outlet circuits and two circuits for our two split air conditioning units.  Three of the outlet circuits are dedicated circuits as required by the electrical code, one for the refrigerator, one for the water pump and one for the washing machine.

We wired our branch circuits using stranded 12 AWG (3.5mm²) THHN conductors for the load and neutral wires and 14 AWG (2.0mm²) for the ground wire. Although this wire is rated to handle 20 amps, we decided to use mostly 15 amp breakers.  A fifteen amp breaker (and a #12 AWG wire) have a nominal capacity of 1,800 Watts on a 120v circuit and 3,450 watts on our 230v system.  If we had used 20amp breakers, our circuits would have a capacity of 4,600.  Using the 15 amp breakers on #12 AWG wire gives us a very considerable margin of safety, but plenty of capacity for any combination of appliances we can imagine on any single circuit.

It was our electrical engineer who specified using stranded rather than solid wire for our branch circuits.  Stranded wire is somewhat easier to work with and stands up to situations where the wire is flexed, better than solid wire.  If you are going to use stranded wire you have to be sure to buy switches and outlets designed for stranded wire.  Stranded wire has a larger diameter than solid wire of the same capacity and therefore will not fit properly into most outlets and switches.  Most (but not all) switches and outlets are labeled as to the type and size of wire they can accommodate. Fortunately, the widely available and excellent Panasonic Wide Series switches and outlets are designated for and work well with stranded wire. We used a mix of Panasonic and Royu outlets.  The Panasonic outlets are much better and much more expensive. Our switches are Panasonic and Anam.  Anam is a mid-priced Korean brand which seems to be of very good quality.  If you are using stranded wire and on a budget, Royu makes a low cost outlet (WD922 and WH922) with screw terminals which works quite well with both solid and stranded wire.

Royu Outlet (receptacle)

Royu Outlet (receptacle)

Mistakenly, we bought Anam switches which were made for solid wire.  Our electricians used them but cut off strands of wire so that they would fit into the switches.  Since we used 12 AWG for our lightly loaded lighting circuits, we have plenty of capacity even with the cut strands.   Perhaps we’ll gradually replace these switches at some point.  We did all of the outlet wiring ourselves using outlets made for stranded wire, so we are confident there are no problems with these.

Outlet labelled for solid wire only

Outlet labelled for solid wire only


Photo of switches with cut strands

Panasonic Wide Series - OK with solid or stranded wire

Panasonic Wide Series – OK with solid or stranded wire

These Meiji outlets also worked well with stranded wire

These Meiji outlets also worked well with stranded wire.  We tinned the leads.  The neutral leads should be white not red.  This was just a photo to show the Meiji receptacle


The above photo shows the interior construction of a Royu brand outlet (left) and Panasonic brand outlet (right).  The cheaper outlets do not seem to be the same quality but less expensive.  The Panasonic housing and contact are quite a bit heavier.  The Panasonic outlets grip the prongs of the plugs so strongly that we have pulled the outlets out of the wall when trying to remove a plug.  Commercial buildings in Iloilo almost always use Panasonic outlets and switches.

There is lots of poor quality electrical gear sold in the Philippines.  Below is a plug made with brass-plated steel prongs rather than brass.  It does not take long for the prong to start corroding.  The capacity of the circuit will be reduced. This is not a problem restricted to the Philippines.  I have a Leviton brand made in USA outlet I brought with me that has rusty terminal screws.  Corrosion of electrical components in the Philippines is rapid, another reason to buy quality products for your own house.  If you buy a pre-built house in a subdivision, did the developer use good parts?

Rusty plug

Rusty plug with non-polarized blades (prongs).  The quality of electrical parts on offer is generally poor.

CONDUIT. This brings us to the mechanics of running conduit for our branch circuits.  Having a detailed electrical plan is essential.  You’ll be required to have one before you get your building permit,  but, in any case, you’ll want a plan.   If you try to make things up as you go, you’ll probably make a mess of things.

Romex-type (NM) cable (several conductors enclosed in a integral plastic sheath)  is available, but not generally used.  In the Philippines, the branch circuit wires are generally run from panel box to outlet to in plastic conduit.  We used individual load, neutral and ground wires of THHN (Thermoplastic High Heat-resistant Nylon-coated) wire in conduit, which is similar to what is used in commercial installations in the U.S.

When embedded in the floor or block walls, the conduit is 25mm rigid plastic.  In the space above the ceiling, the wires generally run in flexible plastic conduit.   The Philippine system of running conduit in the walls can be pretty horrifying when you first see it. Basically, the house is built without much regard to electrical or plumbing runs.  Then, when it comes time to run wires, channels are hacked into the hollow block to accommodate the electrical conduit.  The house can look pretty massacred before the thick finishing coat covers all construction sins.

We tried to neatly cut the conduit channels into the hollow block using a diamond masonry blade in a 4″ angle grinder.  The end result will be the same but we’ll just feel better at least trying to be neat.  Ideally, conduit runs should be anticipated and conduit should be cast into beams so that the beams do not have to be cut later to accommodate the conduit running to the lighting and ceiling fans above the beams.

Conduit in place before pouring concrete

Conduit in place before pouring concrete

Above: before pouring a tie beam at the top of the wall above the location for the panel box, the workers place eight pieces of electrical conduit through the form for the beam. This will provide a path from the panel box for the circuits in the ceiling, mainly light fixtures and ceiling fans.  Put in more conduit than you think you’ll need.  It’s easy to do before the concrete is poured and very difficult afterwards. We should have used larger conduit.  All of these shown are overstuffed with wires, not an ideal situation.

Conduit cut into hollow block wall

Conduit cut into hollow block wall

Above.  Utility boxes which will contain switches are half buried in the hollow block wall.  Boxes are plastic with brass inserts for the mounting screws.  The walls will be plastered with a smooth 1/2″ to 1″coat of finishing cement which is then painted and forms the final finish for both interior and exterior walls.

Conduit will be imbedded in concrete floor

Conduit will be imbedded in concrete floor

These electrical conduits were buried in the concrete floor.  The genius of this system is that wires can be replaced (if necessary) by pulling them through the conduit embedded in the floors.  For this to work, there can be no shortcuts.  The wide arc conduit elbows must be used.  There are no electrical conduit tees.  The blue-color water system fittings can be used with the electrical conduit, but such use may well defeat the ability to pull new wires as the bends are too sharp to pull through.  These outlet circuits embedded in the concrete floors are quite safe from gnawing rodents.

Flexible conduit in attic

Flexible conduit in attic

These photos show how wiring is installed in the attic or ceiling area.  This wiring feeds ceiling light fixtures, ceiling fans, some outdoor lighting and our split air conditioners.  Wiring is in flexible plastic conduit. The silver protrusions are the tops of recessed lighting.  The four stubs of plastic pipe protruding through the top of the wall now carry coax cable to CCTV cameras at each corner of the house.

Recessed ceiling light fixture

Recessed ceiling light fixture

Except for table lamps, all lighting is recessed, no ceiling fixtures or chandeliers except in the bathrooms. We are very happy with the clean look of the recessed lighting, so many exposed fixures are ugly.

After three years in our house we had two recessed fixtures in our kitchen ceiling fail because mice or rats chewed through the short, thin wire leads powering the recessed lights.  They did not touch the THHN conductors which are in conduit.  Our theory is that a thin layer of grease from the kitchen went up through the recessed fixtures and coated the wires.  This made them attractive to the rodents.  Since our attic and roof structures are all cement board and steel, the fire hazard should be minimal.

We have various circuits running outside the house; weatherproof outlets on the porch, circuits to the bahay kubo bamboo guest house, circuits to lights on the perimeter fence posts, circuits for security lighting, circuits for porch lights, circuits for the carport, circuits for outdoor split air conditioning compressors and so forth.  All of these must be anticipated and conduit leading outside installed before the house floor is poured.


This panel of switches controls all outdoor lighting; front and rear gate lights, lights at each corner of the house, and sodium vapor lights in the garage (three way) and yard.

Panasonic timer switch for security lights

Panasonic timer switch for security lights

Our outdoor security lights can also be controlled by this Panasonic timer switch which is wired into our panel box.  We bought this industrial duty switch after having a couple of hardware store electronic timer switches fail.  This allows our lights to be on when we get back after dark and to shut them off at dawn, even if we are still sleeping or away from the house.

We installed a 250 Watt high pressure sodium light in our yard. It lights up the whole neighborhood.  Our neighbors who raise corn like it as sometimes miscreants sneak in and steal their corn. Generally we don’t use it, but can if we feel the need.

HP Sodium yard light

HP Sodium yard light

It lights the yard quite well

It lights the yard quite well

HP sodium tunnel fixture

HP sodium tunnel fixture

We installed this 150 Watt high pressure sodium lamp in our garage.  These lamps are made to illuminate highway tunnels.


Please take time to read the many comments below.  It’s remarkable how little consensus there is, even among those who are knowledgeable about wiring.  Take the information here as hypothesis, not gospel.  We are home owners, not electricians or electrical engineers.  Please feel free to offer comments, suggestions and corrections

Revised November 2018