Only 198 volts on nema 14-50. Yikes!?

[qdeathstar]

I am in a condo building and the wires from the main electrical box run about 300 feet to get to the commercial EV charging stations

So is volts like resistance?

Any resources I can read so I can understand amps, volts, watts, and all of the electrical stuff?

Mainly for my own education. Thanks.

as resistance increases voltage decreases for a certain amount of current. The longer the run is the higher the resistance is, so you address that by increasing the wire. High resistance is dissipation. The energy dissipate is heat. Heat causes fires. Hence the concern.

 

[gaM3changer]

I am in a condo building and the wires from the main electrical box run about 300 feet to get to the commercial EV charging stations

200 volts is a serious voltage drop. It indicates a loose connection or under sized wire, both of which are a serious fire hazard.

it is also possible you have an issue with your utility source or the measurement on the car end but it definitely needs to get checked...

Most commercial charging stations like Chargepoint runs off of 208V so he may not have a problem.

 

[M3BlueGeorgia]

On a separate forum he mentioned hitting 205 at 6A, This supports the theory he is on a commercial 208v connection not a residential 240v connection.

 

[StellarRat]

IMO, if you're starting at 208 and the wire is 120' long it doesn't seem like it's too bad. If you were starting at 240, then yeah it looks like a problem. This calculator shows 204 with a load of 32 amps: Voltage Drop Calculator

 

[RobRain]

IMO, if you're starting at 208 and the wire is 120' long it doesn't seem like it's too bad. If you were starting at 240, then yeah it looks like a problem. This calculator shows 204 with a load of 32 amps: Voltage Drop Calculator

I'm in a townhouse in Whistler (5 units in the building) and I'm seeing 206V. I've reached out to the installer for confirmation that it's on a commercial supply and I'll also check with the strata management team on Monday.

 

[clegg]

El0n: Condo building seems more likely to have a 3-phase 120/208 service. 200V is over 95% of 208V so that all sounds normal.

DavidM34Me: Detached house with 120/208 service seems a bit unusual/rare, but still the most likely explanation. If that's what you have, 198V in itself wouldn't indicate a problem. Do you consistently drop from 205V@6A to 198V@32A? 130 feet of #6 copper wire drops less than 3V between 6A and 32A. Might be worth checking connections in the panel and charger.

 

[dhanson865]

The Canadian standard is CAN3-C235-83.

hmm, looking at some PDFs

View attachment 462783

it seems the Canadian standard still allows for service at a home in 220v. But I know from the interconnect standards you can't send that around from region to region so I'd be surprised if any 220v still existed.

I'd darn sure want to be certain what my main supply into the house was before I made any sort of evaluation on safety to charge there.

So in the US the spec is symmetrical -5%/+5% looking at the Canadian table it just dawned on me the 220v and 250v columns aren't separate service levels it's a range from 240v to those extremes meaning their spec is asymmetrical and roughly -8%/+4%

but they do have 208v off of 3 phase so really you still are looking at either 240v or 208v just like in the US.

The Canadian acceptable range for 208v is 194v-216v. The US 208v range would be 198v-218v. With the US spec being slightly tighter and slightly higher range.

 

[ucmndd]

I'm in a townhouse in Whistler (5 units in the building) and I'm seeing 206V. I've reached out to the installer for confirmation that it's on a commercial supply and I'll also check with the strata management team on Monday.

It is standard for multi-unit residential buildings to be served by 3-phase 120/208v service.

 

[El0n]

Thank you for your responses.

 

[qdeathstar]

Most commercial charging stations like Chargepoint runs off of 208V so he may not have a problem.

didn’t see that bit about commercial service. But we don’t know for certain and a lot of condos around here are split phase, so I would still recommend asking his electrician bout it...

 

[Quorky]

Sorry to hijack the thread but want to get an opinion on my numbers:

14-50 outlet, 6/3 50ft run

At 32amps voltage reads 206
At 16amps voltage reads 208
At 5 amps voltage reads 211

Thoughts if my setup is exhibiting abnormal behavior? I am in Brooklyn, NY

 

[DavidM34Me]

Mystery solved. As it turned out my house is serviced by a 208 V feed. Congratulations to those who guessed it right. Or, I should say, correctly deduced it. Thank you all for your helpful suggestions and efforts.

 

[clegg]

14-50 outlet, 6/3 50ft run

At 32amps voltage reads 206
At 16amps voltage reads 208
At 5 amps voltage reads 211

My readings: 247V @ 6A, down to 243V @ 32A.

It's acceptable/normal for the panel-to-charger feed to lose up to ~6V over a long run (like 230ft of #6 carrying 32A on a 40A breaker). Your 50ft feed should lose 1.3V. My 30ft feed should lose 0.8V.

All four examples here seem to point to the charger internals, charging cable, and circuits in the car losing an additional 3-4V.

tl;dr: expect 3V to 10V loss, depending on length of cable from charger to panel.

 

[earthwormjim]

Sorry to hijack the thread but want to get an opinion on my numbers:

14-50 outlet, 6/3 50ft run

At 32amps voltage reads 206
At 16amps voltage reads 208
At 5 amps voltage reads 211

Thoughts if my setup is exhibiting abnormal behavior? I am in Brooklyn, NY

Seems normal if you have 208Vac service. You can expect your 100ft of total power wiring to be around 0.04 ohms, add in resistance from any electrical contacts, and the UMC's resistance, and it seems reasonable to have around 0.1-0.2 ohms of resistance. At 32 amps, that works out to a 3-6V drop, which is what you are seeing.

 

[lolder]

The car doesn't care about the voltage. When you first start charging before the current ramps up look at the voltage on the car charging screen. After it ramps up to the full 32 amps the drop should only be a few volts.

 

[InTheShadows]

They probably should have gone to next wire size up. When we install them, we design for max 2% voltage drop. You are going to be pulling full current for many weeks worth of time over the life of the car. You want to put the electricity into the batteries, not pay to heat the wires going to your car.

To keep under 2% usually you end up upsizing the wire around 80-90’.

 

[boaterva]

The real question (which I didn’t see but could have missed it) is what was the open-load voltage. That would have told us whether is was 240 or 208. Load will decrease the voltage, of course, but seeing what you start with would have simplified things.

(Reputable electrical engineer here, lol)

 

[Quorky]

Alright, so got my hands on a voltmeter (mine is not available)... looks like we are getting a 208 feed from Coned (1 family detached home). Crazy stuff but what can you do. Tha k you for the replies.

 

[Quorky]

At the service panel



Car

 

[clegg]

If the car reads 208V on a 240V circuit, something is terribly wrong. If that happens at 6A, you can pinpoint the problem by turning up to 32A. Whatever the problem was, it should now be on fire.