Was fixing a bad wiring job between a sub panel and a 240v 2 phase water pump and noticed that my multimedia was only testing it as 190v. Checked back at the breaker and saw the same. Checked between L1 and L2 on a different breaker and saw the same.
My 240v equipment (dryer, oven, water heater, 2 HVAC units) all work fine.
Should I be concerned?
How big of a deal is this? Like call an electrician asap or wait until I have some other electrical work lined up?
If you are showing that low there is something wrong. 240v is the nominal rating but it should be within about 7% of that and you are closer to 20% off.
Most 240V appliances work fine down to around 200V since they’ll often be used with nominal 208Y120 power after voltage drop.
Are you sure you have 240/120V split phase service and not 2 legs of 208Y120?
If so, I’d contact an electrician or the utility company - sounds like the problem is upstream
I’m going to get a new multimeter first. I also have Tesla battery so I should retest with that system shutdown now that I think about.
Yes, def split phase.
I’m no expert, and I live outside the US, but doesn’t the US use 120v not 240?
Edit: I stand corrected
Typical residential is delivered as 2 phases that are moving back and forth 180 degrees out of sync. If you wires just one of those phases you get 120v. Wire them both and you get 240v.
There’s 3-phase but that’s mostly found in commercial buildings, and you typically get either 208v or 120v depending on if you wire one or two of the 3 wires.
Power delivered to homes in the US is Split Phase. Meaning the distribution transformer was wired to a single distribution phase and it is center tapped. So you would get 120vac A to center, or B to center, but 240ac from A to B.
If it was 2 phase they would be 120 degrees out of sync and would deliver 208vac.
Here in the Netherlands you can get 380V power using the same technique. Very useful for powering an induction stove, or if you want faster charging for your EV
Edit: Referring to three phase power, not two phase power. That is why we get 380V and not 460V
Standard is for US buildings to be supplied with 240v center-tapped (single-family), 208Y120 3-phase (light commercial/multifamily), or 480Y277 3-phase (large commercial, light industrial).
120V is never supplied on its own.
