Location: USA:MN
To preface, I’m a refrigeration mechanic, so I only know just enough about three phase power to get into trouble hook things up and make sure they work.
I’m working on a large remodeling project in my home durring which I want to future proof as much as I can (because foam insulation makes changing things later a bitch). I’m going the full 9 yards running conduit and everything. As part of that future proofing I am planning on upgrading my service from 100A to 200A. However, since I’m upgrading my service anyways, I am also strongly considering getting a three phase service. If I ever wanted to stick an electric car charger or other big piece of equipment in then a three phase connection would be handy to have. It also seems like the kind of upgrade I want to get done while the house is mostly gutted rather than trying to shoehorn it in later. So my questions are as follows.
- Do I go with a 120/208V 4 wire service or a 120/240V 4 wire service? My provider offers both to residential customers in my area. There are additional restriction on the service drop for the 240V option. None of those appear to apply in my case but it might make 240V a bit more of a pain to get.
- Do I need to worry about phase balance? Since this is for a single family home most of my power draw is going to still be 120V between a single phase and neutral. Obviously I want to split circuits up between the 3 phases to try to draw on them evenly, but it’s never going to be split perfectly evenly. Is drawing on the phases unevenly going to cause any sort of issue?
- Are there any other footguns to watch out for here? For example, is having three phase power going to mess with my home insurance rates or anything like that?
Disclaimer: I’m from Europe, I only speak 240/400
About phase balance, you are right to wire stuff in a way that splits your power usage as best you can ; there is a simple way of checking it: just measure voltage between neutral and phase under load on each phase. Your risk in case of severe unbalance is to have the stressed-out phase going down, and the other going up.
How much up and down should we start to worry about? 10% is what I heard from my utility company (Belgium). Given that as a residential customer you are never alone on the grid, your chances of really twisting things up are slim.
That’s kind of what I was figuring on the phase imbalance. I’ve seen it before on industrial sites. I just wasn’t sure if a household power draw could cause the same issue or not.