Are you upgrading Services For Electric Vehicles?

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hanklazard

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Alabama
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Electrician
I work in mostly historic neighborhoods and most of my panels and services are usually 125-150 amp. Even many of the 200 amp services I come across have an electric furnace that pulls 70 amps. Are you guys having to upgrade service and panels with every charging station you put in? I rarely come across a house that isn't already overloaded or near it's capacity. I can't imagine adding an additional 50 amp load to most of these houses.
 
Haven't had to yet. If it's borderline, I would tell them to only charge when not using the stove, dryer, etc (if electric). May not have a choice on electric heat though.
 
Little Bill said:
I would tell them to only charge when not using the stove, dryer, etc
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True besides that, its best for people to use the EV circuit from 11 pm to 7a, not many other heavy loads are being used at that time plus the kilowatt cost is a lot less.
 
Everyone around here is doing it.

On the other hand, I did a load calc on my own house and determined that I could not only add a 32A EV charger but we could electrify all but one of our gas appliances (furnace, oven/range, dryer and water heater) and only the last of those five items would require upgrading from 100A to 125A per the load calc. I also did a load calc for a remodel that went all electric with all those same items and double the sq ft and it came in under 150A.

I think the prudence of upgrading may depend more on the age of the panel than the amps rating. Around here most houses built in the last 30 years have 200A services. 30-45 years old usually have at least 125A. If a house has its original 100A service panel from 50 years ago (FPE? Zinsco?) then it's more likely prudent to replace it. If it has a newer service panel that's in good condition and is 125A, it's more likely fine if they aren't already all electric with a 5-ton A/C, a hot tub. Speaking of typical true single family homes, that is.
 
I'm a betting type of person and would venture that adding a 50 amp load to any house with a properly installed 200 amp SE would not cause an issue. Even those small homes with 100 amp services and gas heat. TOD operation would be a plus.

That said, CYA with load calculations and make suggestions as needed.
 
Anyone actually doing a load calculation prior to an installation? Seen a lot of full boats out their and even some that got a second panel full boat. Seems common practice, if there is an open slot just add another breaker. 2 open slots why can't you add an EV charger is the customers response. And if you do a load calc and it indicates it would overload the panel, who cares, there are still plenty of guys willing to install the breakers around here.
How dangerous can it really be? Is the common thinking. If it doesn't trip the breaker it must be OK. I think the long term mild overloading is a bigger issue than the short term major overload that would trip the breaker. The long term I've seen lead to conductor, breaker, panel board heating and breakdown. Even fire.
 
If the customer has a smart meter he should be getting good information on what his load actually is so no load calculation of existing loads would be required. You could use the actual maximum metered load as your starting point.
 
petersonra said:
If the customer has a smart meter he should be getting good information on what his load actually is so no load calculation of existing loads would be required. You could use the actual maximum metered load as your starting point.
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I recently signed up for paperless billing with my POCO. It was an autopay anyway so the mailed bill meant little. The online information about my usage, TOD, etc is extensive. Impressed.
 
ptonsparky said:
I recently signed up for paperless billing with my POCO. It was an autopay anyway so the mailed bill meant little. The online information about my usage, TOD, etc is extensive. Impressed.
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Does it show your daily peak load? I'd think that might be the most important metric for determining if your service is adequate to add an EV charging station.
 
gadfly56 said:
Does it show your daily peak load? I'd think that might be the most important metric for determining if your service is adequate to add an EV charging station.
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TOD profile may be more important since charging can be scheduled for off peak. Some utilities will offer special off peak rates if you let them control when you charge.
 
retirede said:
TOD profile may be more important since charging can be scheduled for off peak. Some utilities will offer special off peak rates if you let them control when you charge.
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If the customer has a smart meter, 220.87 probably is your best bet. The code does not grant any dispensation for TOD restrictions.
 
Another C10 said:
True besides that, its best for people to use the EV circuit from 11 pm to 7a, not many other heavy loads are being used at that time plus the kilowatt cost is a lot less.
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In some places, yes, but in others, no. Not everywhere has TOU tariffs.
 
ptonsparky said:
I'm a betting type of person and would venture that adding a 50 amp load to any house with a properly installed 200 amp SE would not cause an issue. Even those small homes with 100 amp services and gas heat. TOD operation would be a plus.

That said, CYA with load calculations and make suggestions as needed.
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I'm sorry to ask a dumb question, but what is TOD ?
 
retirede said:
TOD profile may be more important since charging can be scheduled for off peak. Some utilities will offer special off peak rates if you let them control when you charge.
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Since there is no way to guarantee that the user will only charge during off-peak hours, I'm not sure this is relevant to your peak consumption and whether there is enough head space to accommodate an EV charger.
 
Another C10 said:
True besides that, its best for people to use the EV circuit from 11 pm to 7a, not many other heavy loads are being used at that time plus the kilowatt cost is a lot less.
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Do these EV chargers have some sort of built in timer to only charge on off hours? So the owner doesn't have to run at at 11pm to start charging?

Would be interesting if they did, and see the power graph spike at 11pm when all the timers went off...
 
ptonsparky said:
I recently signed up for paperless billing with my POCO. It was an autopay anyway so the mailed bill meant little. The online information about my usage, TOD, etc is extensive. Impressed.
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yeah, I logged into my account a couple weeks ago and was surprised to see how granular they can graph your usage now.
They don't have any TOD differential rates though, except for off-peak air, heat, and hot water storage.
 
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