EVSE 40A circuit

[cossie1600]

Turns out the builder only put a 40A circuit for me for the EVSE, I guess that means I can't use the Leviton 40a EVSE? If that is the case, do I just get any 30A one or can I try to get the 32A ones?

thanks

 

[TonyWilliams]

Have an electrician evaluate if you can make that a 50 amp circiut.

 

[GlennD]

40A means that you can charge at 32A ( 80% of 40A ). The Tesla charger respects the J1772 protocol so any EVSE less than 32A will work. You could use a 24A EVSE but why throw away capacity.

I charge my Mercedes Class B ED at 32A (now 34A) currently but I am going to upgrade to 40A and charge late at night so as to not overload my 100A service.

I use an OpenEVSE DIY EVSE that has adjustable current settings and I just installed one of Tony's 40A Quick Charge Power cables. For now until my circuit breaker arrives from Ebay I am charging at 34A. When it arrives I will pull new wire and upgrade the circuit.

 

[Dsinned]

The KEY factor in such matters is the size (or AWG) and also the length of the "dedicated" wiring to your EVSE. This is what determines the current capacity (or rating) of the circuit. In "theory" a 40A circuit breaker would generally require at least 8AWG copper wiring from the breaker box to the load or AC outlet. If the length of wiring is significant - say from 50 to 100' - then a step up in gauge size to 6AWG could be used. If the end to end length of the wiring is much shorter, 8AWG should be sufficient. However, I suspect some "backyard" Electricians with questionable credentials might even say 10AWG is still okay, especially for very short runs, but only if the maximum load does not exceed 32A.

 

[cossie1600]

Once I move in, I will poke at the wire to see if it is 6 or 8 gauge. If it is 6 gauge, I could just swap the breaker to 50A? It is a 100A panel, so I have to be careful about overloading too

 

[jscgvnc]

Short answer: Get an electrician to look at it.

Long answer: Yes, the key factor is the size of the wiring. However, several other things could be a factor. Is there a sub panel in the garage? Is it run in conduit, and is the conduit sized properly for the conductors? Your setup may not have conduit at all but many garages do use conduit. If you upgrade your wiring, will the conduit still be sized properly for the new conductors? So you really need an electrician to evaluate.

The reason that this is required is because the electrical code classifies an EVSE as a "continuous load", as it is likely to run for 3 or more hours. Therefore everything must be 125% of normal rating.

The rating of your panel is not that important. I have 100Amp service and it's not problem, even with an electric water heater and an electric stove. You will probably be charging your car at night when nothing else is running anyway, so you will be fine. If not, you can always have your service(and your panel) upgraded.

And just in case you didn't know, 220VAC@40A is nothing to play around with if you don't know what you are doing. Death and serious injury can result from accidents with it, or a fire if it's wired improperly. Don't screw around, get a proper electrician.

 

[davewill]

Turns out the builder only put a 40A circuit for me for the EVSE, ...

Once I move in, I will poke at the wire to see if it is 6 or 8 gauge. If it is 6 gauge, I could just swap the breaker to 50A? It is a 100A panel, so I have to be careful about overloading too

Color me confused. In your first post you say the "builder" only put in a 40a circuit implying this is either new construction or is a big remodel, but nobody would put a 100a service in new construction. I doubt the local code would even allow it. Is this "panel" actually a sub-panel for the garage? If so, it's likely no problem at all. Otherwise, you need to total all of the loads, (not the breakers, the actual appliance loads) to see if you are crowding the capacity of the panel with everything on. some items like heating and air conditioning can be assumed to not be running at the same time. Unusual loads like a welder, you can make some personal rules about (like you won't weld and charge the car at the same time, probably a good idea anyway).

 

[smkettner]

Just get a 30a or 32a EVSE and start charging.
My 30 amp Schneider works just fine charging RAV4 in about 5 hours if super low. (normal charge)

 

[cossie1600]

Nope, they put in a 100a box. I saw the big breaker. The house has a small solar system and gas heater/stove, maybe 100a is all it needs

 

[cossie1600]

Okay I moved in. The other poster is right the house is 200A. The main panel is 200A with a sub-box going into the garage at 100A. They have a 40A circuit breaker to my EVSE. I guess I probably can't upgrade to a 50A without redoing a bunch of wiring? Is it worth it hiring an electrician out to just look to see if the wiring is capable for more?

 

[fromport]

Okay I moved in. The other poster is right the house is 200A. The main panel is 200A with a sub-box going into the garage at 100A. They have a 40A circuit breaker to my EVSE. I guess I probably can't upgrade to a 50A without redoing a bunch of wiring? Is it worth it hiring an electrician out to just look to see if the wiring is capable for more?

Really depends on the wire used between the breaker and the evse.
disconnect the breaker and see if there are markings on the wire which state the awg

 

[dstjohn99]

Okay I moved in. The other poster is right the house is 200A. The main panel is 200A with a sub-box going into the garage at 100A. They have a 40A circuit breaker to my EVSE. I guess I probably can't upgrade to a 50A without redoing a bunch of wiring? Is it worth it hiring an electrician out to just look to see if the wiring is capable for more?

You already invested in the 40amp charger. I recommend making your service adequate for using it. Be aware that the 80% limitation on rated output only applies for continuous usage (two hours or more), which is very likely to happen regularly. It sounds like the 100 amp sub-panel is in the garage, so the length of the wires between the sub-panel and your L2 EVSE is likely relatively short (less than 25'?). Therefore, even if you need to upgrade the wire and the breaker, it should cost less than a 32 amp EVSE.

 

[cossie1600]

Anyone know of a licensed electrician in San jose??

 

[cossie1600]

Been getting quotes of $400 to $500 is that good??

 

[davewill]

Been getting quotes of $400 to $500 is that good??

It kind of depends on what you're getting for that. If they are going to open the drywall, replace the wire, repair the drywall, then I'd say it's really good. If they're going to mount conduit on the wall, then it's just OK. BTW, if they are telling you they don't need a permit or inspection, then cross them off the list no matter how good the number. The permit process is there to protect you and your home from shoddy work.

If you ever think you might have a second plug-in, you might just want to have them run a second circuit rather than replace the one you have. It shouldn't cost any more.

 

[fooljoe]

Been getting quotes of $400 to $500 is that good??

Have you tried talking to your builder and asking them to fix it? If you told them you needed a 50 amp circuit and they installed a 40 amp one, seems to me that's on them to fix. I'm assuming you paid them hundreds of thousands of dollars to build you a house, so they should just eat the $500 extra electrical job to make things right. It's at least worth a try.

 

[davewill]

Been getting quotes of $400 to $500 is that good??

Have you tried talking to your builder and asking them to fix it? If you told them you needed a 50 amp circuit and they installed a 40 amp one, seems to me that's on them to fix. I'm assuming you paid them hundreds of thousands of dollars to build you a house, so they should just eat the $500 extra electrical job to make things right. It's at least worth a try.

I did much the same. I had the builder install my 40a circuit for my Blink (cost me almost $800). I kept trying to tell someone WHERE in the garage I wanted the outlet, but I never got hold of anyone so they just put it where the electrician decided. I made them move it on their dime...which wasn't all that much since the electrical sub was still on site, and he did his work in an hour, then their drywall repair guy just stopped by and patched it up.

 

[Dsinned]

Sure, if being able to fully recharge your RAV4 in 1 to 2 hours less time would be desirable.

 

[cossie1600]

I have a better chance of seeing god than getting them to fix stuff. They left some of my kitchen cabinet doors missing and took off....

 

[GlennD]

I have a better chance of seeing god than getting them to fix stuff. They left some of my kitchen cabinet doors missing and took off....

Speaking of God:

I saw bumper sticker yesterday. It said honk if you love Jesus. Text if you want to meet him.