Incoming utility cable capacity - A cautionary tale

[Babylonfive]

At least in PG&E's territory in California, they have their own set of rules, not dependent on the NEC, for what happens before the meter. I have a 200A service that at the time was fed by a 10kVA transformer shared with a neighbor! As the result of installing a large PV system (36.7kW DC / 30.5kW AC / http://www.solarwarrior.com/), ... <Snip>
After the hazmat cleanup, PG&E replaced it with a dedicated 25kVA transformer. I'm sure one day I'll smoke that as well; with 5 EVs "full rate" charging them all at once is a 290A load (which I obviously can't do on a 200A service). The good news is that I have two conductors of 500MCM copper (and a somewhat smaller neutral) coming down from the poll.

Adelman, what a great setup you have! I recommend everyone to check out the blog referenced above... thank you for leading the charge (no pun intended) on net-metering and solar system support, in general. Great! I hope to build a 5kW system someday, but wow 30kW is amazing.

 

[MitchL]

Wow, this is an amazing story. Glad everyone's safe!

I've recently updated my house from 125A to 400A, added 10.5KW of solar, and of course now have the Model S (HPWC eventually) plus an electric garage heater and other new loads. All was done with the blessing of PG&E, so they were aware of everything.

A few days ago I got the notice from PG&E that they're shutting off my neighborhood for a day (about 10 houses) for an "equipment upgrade." There's a transformer vault at the intersection on the notice.

Makes me wonder, after reading this story and the comments, if PG&E is being proactive, or if I've pushed the local transformer over some limit and things are getting dangerous. I'd think if it was me specifically they'd tell me to reduce peak usage until the upgrade is done.

/Mitch.

 

[Ceilidh]

First of all, Thanks for posting this story and I am so glad to hear that nobody was hurt.

As others have mentioned, and as I have posted before elsewhere, make sure you talk to your utility company for an inspection of your wires from the transformer to your house, as well as the transformer that serves your house itself. This is even more important if you have configured with twin chargers and a HPWC.

I contacted PG&E here where I live and they indeed have to upgrade my transformer. However, with all the EVs and solar arrays going up in the Bay Area, they have about a 2-3 month backlog in getting around to the upgrades. I had my system inspected about 2 months ago, and work to replace the transformer is scheduled for sometime in February. So my advice is to call your utility company VERY early before you get the car. I was told that until the transformer was replaced I should dial down the amps to no more than 50 until the transformer is swapped once my HPWC arrives, specifically to avoid the scenario described here, although in this case it seems the cables were the problem rather than the transformer itself. Stay safe folks!

Cheers.

 

[Oyvind.H]

As a stockholder I became anxious when I read the discussion about moderators reviewing a post about a fire. Some people (i.e. desperate shorters, Jalopnik and others who don`t care about the truth) would love to get their hands on a "Tesla fire" story and totally misinterpret it. And when the story is first retold with false info, it doesn`t matter if the fire wasn`t caused by the car.

Glad noone was hurt! And as a stockholder I am glad Tesla is not to blame for the fire. But I do have one question; how could this happen? Don`t you americans have a main circuit breaker directly after your electrical intake? Here in Norway everyone has a main circuit breaker sized properly according to the dimensions of the cables entering the house. I am much more worried about people trying to install their own outlets in garages etc....

 

[FlasherZ]

A Don`t you americans have a main circuit breaker directly after your electrical intake? Here in Norway everyone has a main circuit breaker sized properly according to the dimensions of the cables entering the house. I am much more worried about people trying to install their own outlets in garages etc....

This was prior to the main circuit breaker -- this was the "intake". Electric companies are permitted to undersize service entrance cables. But as mknox mentioned, this may very well be at the splice point at the top of the weatherhead, and it was a weak point.

I am just as concerned about the equivalent of installing a gas pump in everyone's home and the type of "rigging" that takes place.

 

[Robert.Boston]

As a stockholder I became anxious when I read the discussion about moderators reviewing a post about a fire. Some people (i.e. desperate shorters, Jalopnik and others who don`t care about the truth) would love to get their hands on a "Tesla fire" story and totally misinterpret it. And when the story is first retold with false info, it doesn`t matter if the fire wasn`t caused by the car.

... which is why the original "placeholder" post was put into moderation. This aspect has been discussed in its own thread: Sensationalistic titles with no content/censorship

 

[mknox]

But I do have one question; how could this happen? Don`t you americans have a main circuit breaker directly after your electrical intake? Here in Norway everyone has a main circuit breaker sized properly according to the dimensions of the cables entering the house. I am much more worried about people trying to install their own outlets in garages etc....

Electrical burn offs are not uncommon to those who work in the industry, and are typically due to a failure of a splice or connection. I have completed a smart meter rollout at my utility, and while our deployment went mostly without incident, there have been lots of reports of smart meters "exploding" or "catching fire". What is actually happening is that installers may not be inspecting the meter socket for broken lugs, or the meter may not seat properly or may break a weak lug when it is installed (meters essentially "plug in" to a receptacle). The bad connection overheats and melts or catches fire. Smart meters were all over the news as a result, when it actually had nothing to do with the smart meter. Meter bases can fail, and were failing like this long before smart meters came on the scene. This incident is similar in that regard. There was a failure of the service lines coming into a house where an EV happens to be, but the EV has nothing directly to do with the ensuing fire.

EDIT: Funny, I was just sitting in my office and overheard one of our operations supervisors talking about a secondary burn off that he had just dealt with!

 

[gregincal]

All of this is one of the reasons I'm anxious for a charge timer. Not just for rate reasons, but also so that the EV load happens at a time when I'm not otherwise using electricity in my house. Most people don't have an additional huge load in the middle of the night :wink:

 

[gg_got_a_tesla]

All of this is one of the reasons I'm anxious for a charge timer. Not just for rate reasons, but also so that the EV load happens at a time when I'm not otherwise using electricity in my house. Most people don't have an additional huge load in the middle of the night :wink:

Except when running your AC full blast in mid-summer!

So, followed up with PG&E's "Building and Renovation Services" folks at Building and Renovation Services, 1-877-743-7782. They've created a new application there for a site visit to see if service upgrades (where I'd have to take up any costs over $1,918) or system upgrades (PGE takes care of all the cost there). Hopefully, nothing'd need to be done...

 

[mknox]

All of this is one of the reasons I'm anxious for a charge timer. Not just for rate reasons, but also so that the EV load happens at a time when I'm not otherwise using electricity in my house. Most people don't have an additional huge load in the middle of the night :wink:

You'd think, but with Time-of-Use rates coming on strong, a lot of people are trying to shift loads into off peak periods. In my case (and I don't even have my S yet) about 93% of my consumption is in Off Peak (7pm - 7am + weekends/holidays) with the remaining 7% in Mid and On Peak periods. I run my dishwasher at night, have a timer on my electric water heater, do laundry after 7 or on weekends etc. and in the summer, "pre-cool" my house before setting the a/c back during the day. I hope to do all of my EV charging at that time too.

 

[adelman]

All this talk of "notifying PG&E" about the additional load. Especially if you have solar, if you notify PG&E about an additional load, it is their M.O. to tell you that (1) it is going to cost you to have the study the problem and (2) after they study it, it is going to cost you more to fix it.

It might be cheaper, not safer, to just let their undersized equipment burn. They'll replace it with bigger at their own cost.

If you do contact them, I'd tell them that you're just making a courtesy call, and that you have sufficient existing service to satisfy the new load. You're just making the call as a courtesy in case THEY want to check if their equipment is up to the new load.

 

[Ceilidh]

If they tell you it will cost you, tell them no it won't.

If people encounter this, then they are talking to idiots at PG&E. As with the rest of the US, the utility is responsible for everything until it hits your house. Period. It is up to them to satisfy your electric demands. I had no problems with them in that regard, and they have to upgrade my transformer. They never once tried to tell me it would cost me, because they cannot charge me for their responsibility. If you encounter someone who says otherwise, they either misunderstood you, or are an idiot. The only thing that can add cost with the EV addition is if your house is going to take on a second meter for the split EV rate (notice this is something on your house, not prior to the wire from the utility hitting it).

I am really surprised that GG and others keep getting quoted fees. You aren't a business with some wacky increased load need, where the rules change. You are a simple consumer with an increased requirement for electricity... which it is their job to provide.

I would be interested in hearing what they told you the difference was, GG. As far as I know, what I said above holds true with an EV purchase. Perhaps someone can correct me if the law states otherwise.

Cheers.

 

[FlasherZ]

In my case, the power company even supplied the new meter base for the upgrade (although I had to install it). All other components -- the 2 engineering/planning trips, the installation, the new service cable, the transformer were paid for by the PoCo because they're required to do so.

 

[gg_got_a_tesla]

Thanks for the input, guys. I'll make sure tomorrow that the PG&E folks are on the same page here wrt costs.

 

[NigelM]

As with the rest of the US, the utility is responsible for everything until it hits your house. ........

Perhaps someone can correct me if the law states otherwise.

This is not universally correct. In our case the utility company is only responsible for the service to the roadside. The home owner is responsible from the road to the house. There are a few exceptions grandfathered in but otherwise 99% of homeowners here are financially responsible for the cable from the street to the meter.

(When we installed our first PV system we needed an upgraded supply and I spent a useful hour researching the property history to establish that we were on a grandfathered lot from the early Sarasota city development, which saved me a few thousand dollars.)

 

[mknox]

In my case, the power company even supplied the new meter base for the upgrade (although I had to install it). All other components -- the 2 engineering/planning trips, the installation, the new service cable, the transformer were paid for by the PoCo because they're required to do so.

That's not the case everywhere. Here in Ontario, the consumer is required to pay for all of the service entrance equipment upgrades (including the meter base), and if service conductor upgrades and (sometimes even) transformer upgrades are needed, the consumer pays (via a complex formula) for that too. Our regulator has determined that utility incurred costs that benefit only one consumer must not be shared by other consumers who do not directly benefit. The "complex formula" I mention above is designed to offset the capital costs of the upgrade with the increased revenue the utility will realize as a result of the new load.

- - - Updated - - -

All this talk of "notifying PG&E" about the additional load. Especially if you have solar, if you notify PG&E about an additional load, it is their M.O. to tell you that (1) it is going to cost you to have the study the problem and (2) after they study it, it is going to cost you more to fix it.

It might be cheaper, not safer, to just let their undersized equipment burn. They'll replace it with bigger at their own cost.

If you do contact them, I'd tell them that you're just making a courtesy call, and that you have sufficient existing service to satisfy the new load. You're just making the call as a courtesy in case THEY want to check if their equipment is up to the new load.

Be careful. You may have agreed to Conditions of Service terms as part of your contract for the delivery of electricity. If you damage utility-owned equipment (cables, transformers etc.) as a result of an unreported upgrade or significant load addition, you might be on the hook.

 

[Ceilidh]

@NigelM: I stand corrected.

Cheers.

 

[FlasherZ]

That's not the case everywhere. Here in Ontario, the consumer is required to pay for all of the service entrance equipment upgrades (including the meter base), and if service conductor upgrades and (sometimes even) transformer upgrades are needed, the consumer pays (via a complex formula) for that too. Our regulator has determined that utility incurred costs that benefit only one consumer must not be shared by other consumers who do not directly benefit. The "complex formula" I mention above is designed to offset the capital costs of the upgrade with the increased revenue the utility will realize as a result of the new load.

I imagine it's a tough business decision to have to make. I grow happier and happier with my experience every time I read about how many benefits I have. My PoCo is a co-op from the REA days.

I do know that in some areas the meter base specs are provided to the consumer and the consumer must purchase and wire all the way to the weatherhead, where the splices are made by the PoCo (and in ModelS1079's case, may be the source). It's a patchwork of regulation, so the moral of the story is that you have to ask, I suppose.

 

[adelman]

Be careful. You may have agreed to Conditions of Service terms as part of your contract for the delivery of electricity. If you damage utility-owned equipment (cables, transformers etc.) as a result of an unreported upgrade or significant load addition, you might be on the hook.

Well, in my case, I ended up in litigation with PG&E over the $650K in upgrades to their infrastructure that they wanted me to pay for in order to connect my PV system. The California Public Utilities Commission Court agreed with us that we had already paid for a 200A service and could do whatever we wanted within its limits (200A peak, 170A continuous) and that the utility was responsible for any upgrades. That is, as long as I didn't upgrade my service entrance capacity. Once the CPUC ruled that the utility was responsible for these upgrades, they decided that they weren't needed and never performed them.

In other words, the damage to utility-owned equipment wasn't our fault even though we have a significant load increase, because we had already paid the utility to delivery a 200A service, and were entitled to use it. In this case the cause of any damage to the utility-owned equipment was the decision by the utility to install undersized equipment based on a statistical gamble that most customers wouldn't use the full service capacity that they had paid for, and their profits would be increased by installing undersized equipment and replacing it only when it fried.

Like I said before, I don't have a problem with notifying the utility that you've increased your load, but if you do this in PG&E territory I would make it clear to them that it is a courtesy-call only, that you already have sufficient capacity paid for when your house was built, and you're not asking for any upgrades.

 

[mknox]

Sorry adelman, I misunderstood. If you're not upgrading your main 200 amp service then no, you should not be on the hook for any infrastructure costs. Utilities like PG&E should be able to fund any infrastructure upgrades (for whatever reason) based on the increased revenues they'll get from additional electricity sales.