Weak power at new place

Hi all! Wanted to get a little advice from the locals here -- and I know Mitch you've got experience with this so I'm hoping you'll chime in

At my new place in Arlington, MA (electricity provided by NSTAR), I'm getting maybe 229-232V idle and 215-222 under 40A load (brand new 6 gauge temporary run I installed) I'm upping to 200A service next weekend and will be pulling 80A and I'm pretty sure that's going to cause some problems, perhaps even blow the transformer. I called NSTAR to complain and warn them about my upcoming load a couple weeks ago and they said they'd check and made an explicit note to call me. I haven't heard back. I'll call again tomorrow but wanted to know if there's a better way. I'm just calling the main number and going thru the menu until I find a human.

Suggestions?

I called again -- it's not like the people that I initially get a hold of understand the technical details but I said I'm concerned I'm going to blow the transformer and take out the neighborhood blah blah blah ... and that under 1/2 load I'm measuring 215v. The real issue is they supposedly sent someone and repaired something (nothing has changed) but I never got a phone call. So I emphasized, and she emphasized on the work order, that I need a phone call to describe what I'll be doing and what I'm seeing. She couldn't give me an ETA on a return call. I may end up having to take out the neighborhood :-( I'll wait until I have a generator first heh.
Power lines are overhead. I keep forgetting to locate the transformer, though thus far I haven't seen any pole-mounted ones. Not sure where they are yet, so no idea how big they are or how many people they serve. The power to the house is relatively crummy -- I can see changes in the voltage via the lights quite frequently. So far the Model S hasn't cared about that though, thankfully.

mknox said:

The utility is responsible for voltage levels at the service entrance, not the utilization point as there could be voltage drop within the building wiring. If possible, you should try to measure at your panel under no load and load conditions. 215 volts would be considered just outside of normal operating conditions on a 240 volt circuit. I suspect you're probably a volt or two higher at the demarcation (panel) point. There's really no way to tell if you have an undersized transformer, undersized lines or some combination. Everything may in fact be adequate but since you mentioned not being able to find the transformer, the voltage dips may just be a result of line losses over a long distance.

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Yep, I know I'll be a couple volts lower at the usage point vs. entrance point and since it's a new temporary install I just did, I'm comfortable knowing it's not a big loss from the 50A breaker to my 14-50 (I observe low voltages elsewhere in the house, too). It's possible the panel or something else I'm responsible for is at fault (read on...)
This is only under 40A load. I'm going to dip that under 210 or worse when I put an 80A load on it. I'm having my 200A installed this weekend so I'll try to remember to measure it as close as possible to the service entrance (e.g. right before the meter) while things are opened up. The 200A upgrade may uncover and fix a customer-side problem, too -- we'll see.

Well apparently they stopped by, pulled the meter, and checked the voltage. "perfect 240/120. Right sure maybe at 12:30pm when you tested it, and without load. And ignored my ask to call me for the second time. So guess what, you'll be coming back out here. *sigh* I'll call them AGAIN and instead of making this a "low voltage" call, tell them I'm adding 20kW continuous load.
BTW I checked voltage at the panel inlet vs what the car is reporting -- a 2V difference.

Service upgraded. Today I started at 232 volts and dropped to: 226 @ panel / 219 @ car (80 amp draw). So, better than I feared, but -- I think I have a "right" to have at least 233 even under load, so I can now at least call nstar and tell em hey I have a brand new drop and it's still sagging too much. I found the transformer -- it's several poles down the road -- looks like it's serving quite a few homes and looks like your normal small pole transformer.

I tried to plug the car directly into the eu6500 and no go -- it saw that it wasn't grounded. While the genny is connected to the house, that shouldn't be an issue, but I haven't tried it yet. It got really late before the main service upgrade and genny input was complete. I'll try it out tomorrow. I'm also having a problem with the generator hunting/surging under certain loads :-( so I need it serviced. Damn thing's brand new and this is the first time I've used it and it's busted. *sigh*

mknox said:

240 volts is the "nominal" level. Normal levels (which you have a right to) are 220 to 250 volts. At least here in Canada. I suspect the US has similar min and max voltages since a lot of the regulations are harmonized. There is likely a voltage drop on the secondary mains between the transformer and your service drop. This is normal, and doesn't necessarily mean anything is undersized. I can see the voltage vary by several volts at my own house with no change in my load at all due to other customers on the street. If your utility were to bump the taps up on the transformer to compensate for the line losses to your drop, other customers close to the transformer may suffer from the opposite problem and have high voltage.

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NEC here recommends no more than 3% loss to my panel and 5% to the plug (if I'm reading this right) -- either way my electrician said I'm "entitled" to no more than 3% loss at my panel.

The setup here is ridiculous -- one small transformer serving probably 20 houses or more and all of them in series off relatively small aluminum wire on the pole. I see voltages from 240 to 215 here *without* load at my house. I see the lights changing output all the time (meaning, multiple times per minute). It's quite undersized here. This should be a fun conversation, if I can just get my damn message to the tech.

I talked to the town's Nstar service engineer ... apparently there's a form for the electrician to fill out for the service upgrade we did (they don't usually notify the town for various reasons), which includes a spot for the 20 kW load I'll be adding. The service engineer triple-checked me on that 20 kW number so I at least got her attention We'll see where this goes ....