EVSE Install questions for electricians

[squirreltech]

Any Electricians in the group? I'm looking to install a Level 2 EVSE in my garage. I have 100amp main service panel in my basement and a few major appliances running from it. Air Conditioning, electric stove, and dryer on the main panel. the main panel is full for breakers. We have 2 sub panels, one runs on a 40 amp breaker and is right next to my main panel (has a pool pump and pool gas heater on it), the other goes to the garage and that's the one I want the EVSE installed from if possible. It runs from the main panel on 3/6 AWG wire and has a 50 amp breaker on the main panel. Hooked up in the garage are a few receptacles with small tools often connected, a full size fridge that draws 7.2 amps max, and a heater plugged into a 14-50 receptacle and running on a 2/10 wire and 30 amp breaker on the sub panel (I know this is a mess). We don't really need that heater and it will be disconnected, and the wire and breaker removed. So it will have 3 12 amp breakers and a 20 amp breaker. the only thing running from that garage panel is plugs, the lights and garage door openers are off the main panel. What I'm hoping is that we have enough room to install a 40 amp charger (so 50 amp breaker) in the garage with a 14-50 plug. Could you let me know if that's possible given the current setup. I pulled my hourly energy usage from my service company and the highest draw was at 6pm in a night in July at 8.24 kwh. That would indicate the max -ish I've ever used in amps was 34.333 amps, which tells me I have plenty of room with 100 amps and shouldn't need to upgrade to 200 amps. Is this correct or am I missing something? also, Is it feasible to install a 40 amp EVSE off the 50 amp panel in the garage? I have a grizzle EVSE so I could set it to 32 amps vice 40 if that would help or I could remove the fridge from the garage. thoughts?

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[daemonic3]

I am not an electrician, but from getting quotes from 4 of them and requesting a permitted install, they were all mentioning the load analysis they have to do. I have 200A service and was apparently on the hairy edge for adding another 50A. The point I was told was even if I know how to load balance and what not do plug in or run at the same time, I may not be the owner forever and new owners could cause a fire, and liability gets traced back, etc, mess upon mess.

So I'm just *guessing* no licensed electrician would take it on as the 100A vs 200A service was the first question each asked. I guess doing it yourself is the risk that if any fire starts that insurance will deny the claim? I don't know.

Best of luck, now I'm going to follow this to see what experts say.

 

[babgvant]

The code will depend on where you live, I've had lines put in in IL and WI without any complex analysis. Rules could be different in different states, or Canada... They looked at the panel, verified that there was space, and did the work. Although we had 400 (IL), 150 (WI) service so that might play a role.

Stupid question: why not use the existing 14-50 with an EVSE configured to do 24A? That should be fine in most cases.

If it's not, you should easily be able to install a 40A line to a 14-50 off the 50A panel and charge the car at 32A with the EVSE that came with the car. Disconnecting the heater would be important in that scenario to avoid overload.

 

[Maquis]

You need an electrician perform an NEC load calculation. That will tell you exactly how much load you can add. Then you can install an EVSE that has a hard limit that won’t allow you to exceed the max allowed from the load calculation.
If the electrician tries to tell you you have to upgrade your service without performing the calculation, say “thanks” and call somebody else.

 

[squirreltech]

The code will depend on where you live, I've had lines put in in IL and WI without any complex analysis. Rules could be different in different states, or Canada... They looked at the panel, verified that there was space, and did the work. Although we had 400 (IL), 150 (WI) service so that might play a role.

Stupid question: why not use the existing 14-50 with an EVSE configured to do 24A? That should be fine in most cases.

If it's not, you should easily be able to install a 40A line to a 14-50 off the 50A panel and charge the car at 32A with the EVSE that came with the car. Disconnecting the heater would be important in that scenario to avoid overload.

The existing run to that heater is only 2/10 wire. I don't think that's proper for the amperage nor is it 240 volts if it's just 2 wire. It's also not in an ideal location in the garage. So I'll just be removing it completely and re-wire with 6AWG (for future expandability, should I upgrade the panel/service in the future) and put a 30 or 40 amp breaker on it. whatever the electrician recommends for amperage that I can support. Electrician is coming by today to have a look. Thanks for the suggestions.

 

[babgvant]

The existing run to that heater is only 2/10 wire. I don't think that's proper for the amperage nor is it 240 volts if it's just 2 wire. It's also not in an ideal location in the garage. So I'll just be removing it completely and re-wire with 6AWG (for future expandability, should I upgrade the panel/service in the future) and put a 30 or 40 amp breaker on it. whatever the electrician recommends for amperage that I can support. Electrician is coming by today to have a look. Thanks for the suggestions.

Doh, I saw 14-50 and didn't process the limitation ?. Although, as long as the the 14-50 is grounded, and the 2 wires are wired to the hots; which they should be on a 14-50. I don't think neutral is optional from a code perspective (14-50 on a 30A circuit is a no-no though AFAIK), but you do see it missing occasionally. Technically that configuration should work with an EVSE provided it's configured at 24A (EVSE don't use neutral), although not ideal for several reasons .

 

[mkhuffman]

So, electrical engineer here, but not an electrician. Which means I understand what is required, and what can burn down your house, but I am not a code expert.

The load analysis others have recommended makes sense, but in the end your house needs to be protected by the appropriate breakers, wires and outlets. Which means if your breaker is properly sized for the wire and outlets, you should be safe. Again, I am not a code expert.

So if I were you, I would do three things:
1. Replace your garage 30 Amp subpanel with a 50 Amp one. You have wire that can support that load, and you have the proper 50A breaker in your main panel.
2. Run 6/3 from your 50 Amp subpanel to your existing 14-50 outlet, or install a new one. Either way, you should use 6/3 and put a 50 Amp breaker on that circuit in your new subpanel.
3. Use the new 14-50 outlet to power 32 or 40 Amp EVSE. You can use the Ford supplied 32A one, but it sucks and will likely overheat in the summer. Get a new one that works in all seasons, and can provide 40 Amps of charging current. 40 Amps is the most you want to run through a 50 Amp breaker.

Then you are good to go. Yes, you could exceed 50 Amps in that subpanel because of the other circuits, but then that is what the breaker is for. If you don't want to throw a breaker, then just don't use any power tools when charging your car. Easy peasy.

Another option is to replace the 50 Amp breaker in your main panel with a 60 Amp one, and do the same thing I described above with a 60 Amp subpanel. Then you can direct wire a 48 Amp EVSE to your subpanel. Again, you may overload the circuit if you use other devices connected to your subpanel, but that is what the breaker is for.

You know if you are pulling 48 Amps via your EVSE that is practically half what your house is able to provide. So if your water heater and dryer are running, you could hit the limit and blow that 100 Amp breaker. When one breaker is thrown it is annoying, but shutting down your entire house is another story. Maybe you can get Natural Gas and get a NG water heater, dryer, range and furnace? That should more than remove any concerns over the main breaker.

40 Amps via a 14-60 outlet is pretty good though. And probably that is good enough considering your situation.

BTW - I would not use the power company data you referenced to determine the max power/current. You can get peaks that last seconds or minutes, that will greatly exceed the hourly average. The best approach is to get a power monitor, like the one I use (emporia), which allows you to see exactly how much power you are drawing every second of every day.

Or you can add up the current requirements for each device connected. The problem with that approach is I have found the actual current to be much less than what you get when adding up devices. That is because of timing, when things turn on, off, etc.

Long winded response. Good luck!

 

[Mach-Lee]

Oh boy, I would not want to charge an EV through a Federal Stab-Lok breaker. That's too risky for me. I'd have to replace the main panel first. Go read up on Stab-Lok breaker fires first.

If I were your electrician, I wouldn't take the job unless you agreed to replace the main panel. It would be too risky for me to sign off on installing an EV charger with that Stab-Lok main panel due to liability. So you may run into this when hiring a reputable electrician. Nobody wants to touch a Stab-Lok situation other than a complete replacement.

You will have to get rid of the garage heater completely. I'd have to do a load calculation but my gut says you could safely go with a 32A EVSE on a 40A breaker. A 40A EVSE on a 50A breaker might be too much power for your 100A service if you are running dryer, A/C, and oven at the same time.

You're in Canada so I don't know how to do your load calculation. I know how to do one per the NEC in the US.

 

[AKgrampy]

I too am an engineer and not an electrician. I believe you need to have someone review your panel for code compliance and loading. I too have a 100 amp service and Loading would be tight if I was cooking, running the dryer, and my well pump kicked-in during charging. I charge exclusively at night so not an issue. I believe 100 amp services will be no more in the future as EV’s become more accepted. I am going to look into a 200 amp service next year as a second EV would put my load over the top. Or if I chose to purchase a Lightning and a larger amperage EVSE.

 

[mkhuffman]

Oh boy, I would not want to charge an EV through a Federal Stab-Lok breaker. That's too risky for me. I'd have to replace the main panel first. Go read up on Stab-Lok breaker fires first.

You will have to get rid of the garage heater completely. I'd have to do a load calculation but my gut says you could safely go with a 32A EVSE on a 40A breaker. A 40A EVSE on a 50A breaker might be too much power for your 100A service if you are running dryer, A/C, and oven at the same time.

You're in Canada so I don't know how to do your load calculation. I know how to do one per the NEC in the US.

Wow. I never knew about the problems with Stab-Lok. After a quick search it looks bad.

I think I have to agree with you and replace the main panel before attempting anything I suggested in my previous post. I don't want the OP to burn down his house!

 

[squirreltech]

So, electrical engineer here, but not an electrician. Which means I understand what is required, and what can burn down your house, but I am not a code expert.

The load analysis others have recommended makes sense, but in the end your house needs to be protected by the appropriate breakers, wires and outlets. Which means if your breaker is properly sized for the wire and outlets, you should be safe. Again, I am not a code expert.

So if I were you, I would do three things:
1. Replace your garage 30 Amp subpanel with a 50 Amp one. You have wire that can support that load, and you have the proper 50A breaker in your main panel.
2. Run 6/3 from your 50 Amp subpanel to your existing 14-50 outlet, or install a new one. Either way, you should use 6/3 and put a 50 Amp breaker on that circuit in your new subpanel.
3. Use the new 14-50 outlet to power 32 or 40 Amp EVSE. You can use the Ford supplied 32A one, but it sucks and will likely overheat in the summer. Get a new one that works in all seasons, and can provide 40 Amps of charging current. 40 Amps is the most you want to run through a 50 Amp breaker.

Then you are good to go. Yes, you could exceed 50 Amps in that subpanel because of the other circuits, but then that is what the breaker is for. If you don't want to throw a breaker, then just don't use any power tools when charging your car. Easy peasy.

Another option is to replace the 50 Amp breaker in your main panel with a 60 Amp one, and do the same thing I described above with a 60 Amp subpanel. Then you can direct wire a 48 Amp EVSE to your subpanel. Again, you may overload the circuit if you use other devices connected to your subpanel, but that is what the breaker is for.

You know if you are pulling 48 Amps via your EVSE that is practically half what your house is able to provide. So if your water heater and dryer are running, you could hit the limit and blow that 100 Amp breaker. When one breaker is thrown it is annoying, but shutting down your entire house is another story. Maybe you can get Natural Gas and get a NG water heater, dryer, range and furnace? That should more than remove any concerns over the main breaker.

40 Amps via a 14-60 outlet is pretty good though. And probably that is good enough considering your situation.

BTW - I would not use the power company data you referenced to determine the max power/current. You can get peaks that last seconds or minutes, that will greatly exceed the hourly average. The best approach is to get a power monitor, like the one I use (emporia), which allows you to see exactly how much power you are drawing every second of every day.

Or you can add up the current requirements for each device connected. The problem with that approach is I have found the actual current to be much less than what you get when adding up devices. That is because of timing, when things turn on, off, etc.

Long winded response. Good luck!

Thanks for that detailed reply. The garage panel isn't 30 amps. Just the heater connected to it is in a 30 amp breaker. I believe the panel is capable of 100 amps, but the 3/6 wire running to it should only be 50 amps max as it supports 65 amps. So I can't put a 60 amp breaker on the main panel due to code 80% rule and 125% voltage drop in 100' run. It's not 100' but probably 20-25'. Either way max breaker for 3/6 wire is 50 amp. I will install a new 14-50 plug and I will use 3/6 awg wire for it and like you suggested breaker will be 30 or 40 amp depending what the electrician and inspector say. Also, I do have natural gas furnace, and gas water heater. Just the stove and dryer are the major electrical draws. Again thanks for the detailed reply. Good info.

 

[squirreltech]

Oh boy, I would not want to charge an EV through a Federal Stab-Lok breaker. That's too risky for me. I'd have to replace the main panel first. Go read up on Stab-Lok breaker fires first.

If I were your electrician, I wouldn't take the job unless you agreed to replace the main panel. It would be too risky for me to sign off on installing an EV charger with that Stab-Lok main panel due to liability. So you may run into this when hiring a reputable electrician. Nobody wants to touch a Stab-Lok situation other than a complete replacement.

You will have to get rid of the garage heater completely. I'd have to do a load calculation but my gut says you could safely go with a 32A EVSE on a 40A breaker. A 40A EVSE on a 50A breaker might be too much power for your 100A service if you are running dryer, A/C, and oven at the same time.

You're in Canada so I don't know how to do your load calculation. I know how to do one per the NEC in the US.

I didn't know that about those breakers. Thanks for the info. I'll be sure to ask the electricians coming for quotes.

 

[Maquis]

Oh boy, I would not want to charge an EV through a Federal Stab-Lok breaker. That's too risky for me. I'd have to replace the main panel first. Go read up on Stab-Lok breaker fires first.

If I were your electrician, I wouldn't take the job unless you agreed to replace the main panel. It would be too risky for me to sign off on installing an EV charger with that Stab-Lok main panel due to liability. So you may run into this when hiring a reputable electrician. Nobody wants to touch a Stab-Lok situation other than a complete replacement.

You will have to get rid of the garage heater completely. I'd have to do a load calculation but my gut says you could safely go with a 32A EVSE on a 40A breaker. A 40A EVSE on a 50A breaker might be too much power for your 100A service if you are running dryer, A/C, and oven at the same time.

You're in Canada so I don't know how to do your load calculation. I know how to do one per the NEC in the US.

I totally missed the type of main panel. Good call. Those things are notoriously bad.

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