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?
People like you are why I love Lemmy. Thank you. Even when I was looking online earlier I couldn’t find anything nearly as thorough as what you sent.
So it sounds like 240V would be better as far as sheer power goes but is much more fidly. However, my provider is also unlikely to care too much about balance as far as household consumption goes. If I have 3 phase then the heaviest consumer in my house (hvac) is going to be running on that and therefore perfectly balanced anyways. Basically every other load is going to be intermittent so I shouldn’t ever have an unbalance large enough that my provider would care.
I personally would jump on the opportunity to do 3-phase if it were offered to me. Even if my utility didn’t give me a choice in the “flavor” of 3-phase, the fact is that the appliances which need 3-phase (lathes, HVAC, large servers, certain German ovens, very very large solar systems) almost always can be rewired to either wye or delta supplies, provided the voltage is either 208v or 240v. If the appliance wants 480v 3-phase delta, then you’re truly out of luck.
But that’s why I want 3 phase so much: you can’t (efficiently) supply an appliance needing 3 phase if you don’t have it from the utility, but a utility service providing 3 phase can always be split it down to multiple single phases. And I don’t want to preclude myself from ever owning an industrial-sized lathe lol
I should note that for the 208v versus 240v power dilemma, the prevalence of 208v in commercial settings means that large equipment often already sizes their wiring for 208v. Meaning that you already get full performance with 208v, and giving it 240v is just icing on the cake that reduces the current draw a little bit. For example, a modern arc welder that is built with inverter technology usually is no different on 208v or 240v, but drastically cuts back when given 120v. Likewise, a lathe isn’t going to turn slower just because it’s given 208v rather than 240v, but may have a bit less starting torque. If it were a huge deal, industrial folks would reject 120/208 wye outright.
I work mostly with servers and networking equipment for data centers, which are single-phase appliances but the building is often supplied with 3 phase. We lump everything above 200v – 200v Japan, 208v North America, 230v Euro/Asia, and 240v British/North America – as all the same thing when it comes to calculating availabile power.