I have a building in The Philippines. Electricity there is 220 V dual phase for all the lights and outlets (wired like a US dryer but without the ground).

We are installing solar power and the contractor is installing 230 V single phase inverters (1 230 V hot and 1 ground on each unit).

We also have a 30KV 220 V dual phase generator installed. The utility drop and the generator will be separated from the solar by transfer switches (on just the 1 hot 230 line) but all of the 110 US appliances are wired to the individual 110 lines with a neutral and a ground like in the US.

He says it will be fine, I say it will blow everything hooked to it up and short out the utility feed and generator as well since he will be hooking one of their 110 V lines and 1 of the 110 generator lines to ground. I'm sure no one has experienced this but I would sure like an opinion from a professional.

  • Many folks call 220 or 230 or 240 different things. 2 pole / split 220 through 240 are Basicly all the same since only 1 system will be providing power at a time it won't blow things up. With split phase the neutral is grounded so you have 120v for each hot to neutral or 240v from hot to hot. If this is the case it will be fine.
    – Ed Beal
    Mar 14, 2018 at 16:44
  • 1
    Phillippines wiring is hard even for the experts here to understand. The nation was initially wired with 110/220V split-phase USA-style, and post-independence, for new developments they switched to 230V single-phase as in Europe/Asia. Now they're trying to convert remaining split-phase systems any chance they get. This is creating a real complicated mess, especially with grounds. Typical for the utility to supply 220V split-phase with no neutral or ground, so no wires are near earth. Really messes things up. Mar 14, 2018 at 17:11
  • How many amps of 110V will your 110V appliances use? How much total power would you draw from the utility? Mar 14, 2018 at 17:51
  • It sounds like you need a transformer of your own somewhere in this hot mess... Mar 14, 2018 at 22:36
  • You said they are separated on the 230V line only (good so far) - so basically you have single phase 230V Hot, ground and no 'neutral' the ground is still the ground regardless. I think your electrician is telling you correctly. While this is a bit different scenario I have used the HI / Stinger Leg In the USA for European machines requiring 230V single phase with no issues.
    – Ken
    Mar 15, 2018 at 14:17

2 Answers 2


If you have any 110/115/120V appliances, they can't work on unsplit 220/230/240V, period. In theory they could be ran in series, but the reality is that series work only as long as both loads are perfectly same. If the load varies (as it always do) the overloaded leg will get less than nominal and the underloaded will get more - and those appliances are at risk of blowing. The proper way of running those is to use a transformer to convert 220 into 2x110. Depending on how many 110V appliances you have, it could be cheaper to simply replace them with 220V ones and remove the last remains of 110V wiring.

For connecting 2X0V mains, generator and solar together, it's impossible to tell not knowing your exact wiring. You should consult a local electrician, because 1-pole transfer switch doesn't sound right without clear grounding. Understanding your grounding is the key here and as @Harper says, Philippines grounding is a non-trivial one.

As you're currently describing it, I'd say that solar should use 2x110V inverters with 2-pole switch. But, it's also possible that you already have the 220V/2x110V transformer on the mains line and your contractor simply plans to hook up there.

The situation could be far more dangerous than you're describing. If 220V with 1 leg grounded gets connected to 2x110V center ground, at first everything may seem like it's working, but the moment the mains or generator goes live too, 110V will appear between "solar ground" and "generator ground". Again, it could still appear superficially working, but a person touching the generator or a solar panel casing will get electrocuted with 110V. That's why I can only advise consulting an electrician that fully understands both the Philippines 110 to 220V conversion issues in general and the wiring of your building in particular.


You just need isolation transformers to 'make' a new neutral. Here we have (in old buildings) 127V 2 phases as once we had 127 for light and 230V for 'power' now only 230 but as transformers are old, we still have 230V 2-phase


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