Adding 6-20 or 14-50 to a 100 amp service

[Cosmacelf]

I also have 100A service and a trusted electrician said I need to go 200A if I want to add anything over 20A and pass inspection. I live in a very permit obsessed town. The total cost came in a little over $10k, which is not something we're going to entertain. I called another electrician that's scheduled to give me an estimate next week and told him to cancel for the 200A need. He mentioned that same management device listed above and said it was allowed, so we're keeping the appointment. My question, does anyone reading this have one, or know anything about them? They appear to cost less than $1k, so much more reasonable, but only if they work.

Yes, DCC devices work fine. They monitor your total panel load and if it exceeds a threshold, then it cuts power to the EV charger.

 

[Gwelo]

No direct knowledge but Google does.
fhttps://dccelectric.com/

 

[Mike728]

Yes, DCC devices work fine. They monitor your total panel load and if it exceeds a threshold, then it cuts power to the EV charger.

Thanks. I probably should have asked if anyone on here was using one and how well it's working for them. I understand the concept. I'm actually surprised my town allows it. I'll have to verify that before moving forward.

No direct knowledge but Google does.
fhttps://dccelectric.com/

I did look them up online, which is where I saw what the uninstalled box cost was. Thanks

 

[davewill]

If you search the forum, you'll find a few people who have used them. I think the main thing necessary to enjoying life with one is setting things up so that they virtually never trip. What a bummer if it trips every time you use the heater or A/C, for instance. It's all or nothing, and you can't just dial the amperage back temporarily to make it work. That may mean not getting greedy and wiring for 60a and instead pick an amperage that would only trip the DCC if you turned absolutely everything on.

 

[Mike728]

If you search the forum, you'll find a few people who have used them. I think the main thing necessary to enjoying life with one is setting things up so that they virtually never trip. What a bummer if it trips every time you use the heater or A/C, for instance. It's all or nothing, and you can't just dial the amperage back temporarily to make it work. That may mean not getting greedy and wiring for 60a and instead pick an amperage that would only trip the DCC if you turned absolutely everything on.

The main roadblock with us is our 50A hot tub circuit. Without it, we would be fine w/100A service, per the load calculation. We will never be using both the hot tub and charging, so I don't think it would ever trip.

Since no one has yet to come on and say anything negative about it, I think it will work for us.

 

[ewoodrick]

The main roadblock with us is our 50A hot tub circuit. Without it, we would be fine w/100A service, per the load calculation. We will never be using both the hot tub and charging, so I don't think it would ever trip.

Since no one has yet to come on and say anything negative about it, I think it will work for us.

How do you know that? Can you absolutely guarantee it. Someone may accidentally plug in during the day? A software update may reset your charging settings?

 

[Mike728]

How do you know that? Can you absolutely guarantee it. Someone may accidentally plug in during the day? A software update may reset your charging settings?

How do I know no one will use the hot tub while the car is charging? Because I'm the one who maintains it and the only one who turns it on. My wife has never used it while I was out. Also, that is the purpose of the device, right? In the event of an 80A current draw it will shut the charger off. It seems to be a perfect solution for our needs, vs the $10k service upgrade.

Thanks for the heads-up about the possibility of the charge settings being reset after an update. I'll be sure to keep an eye on that.

 

[MattM24]

How do I know no one will use the hot tub while the car is charging? Because I'm the one who maintains it and the only one who turns it on. My wife has never used it while I was out. Also, that is the purpose of the device, right? In the event of an 80A current draw it will shut the charger off. It seems to be a perfect solution for our needs, vs the $10k service upgrade.

Thanks for the heads-up about the possibility of the charge settings being reset after an update. I'll be sure to keep an eye on that.

That’s the purpose, yes. Seems like you’re set.

Do you have a smart meter where you live? Have you looked at your actual electrical consumption? It won’t help with the load calculation part (unless you live in a place that allows that), but it would help you get a feel for how high you could set that device and not have nuisance faults.

 

[mswlogo]

I would not even think of putting 14-50 on that setup. And you don’t typically need it. You might get away with the 6-20 which is typically all most need. Going 120V sucks but better than not charging at home at all.

One option is a dryer buddy that will switch to dryer if in use and then back to car when not in use.

 

[Mike728]

...
Do you have a smart meter where you live? Have you looked at your actual electrical consumption? It won’t help with the load calculation part (unless you live in a place that allows that), but it would help you get a feel for how high you could set that device and not have nuisance faults.

Yes we do. I haven't looked, but I will. Thanks for the advice!

 

[davewill]

How do you know that? Can you absolutely guarantee it. Someone may accidentally plug in during the day? A software update may reset your charging settings?

That's the reason for the DCC device. If it happens that the house draw is too big, the car charging gets interrupted.

 

[Eric33432]

What did you do and how do you like it?

 

[flai54]

I also have a 100A and I did a NEMA 14-50 for my condo complex. What made me decide to do this was because when I filled the local city permit and I had to calculate the total wattage that can be used for a 100A service (48000 watts max), I was far below that (around 25000 watts). On top of that I only charge during off peak hours so even the things like my living room, bathroom, bedroom, kitchen would be running on the minimum. Of course electricians will say you need to get a 200A panel but again I think it depends on the size of your home and also how much additional flexibility you want to additional plugs besides the EVSE.

Just for context, I have a gas dryer, gas water heater and gas stove which would be major users of the electric panel for my condo complex. If more than 1 of these were electric, I would not recommend installing it on a 100A panel.

 

[Tronguy]

I also have a 100A and I did a NEMA 14-50 for my condo complex. What made me decide to do this was because when I filled the local city permit and I had to calculate the total wattage that can be used for a 100A service (48000 watts max), I was far below that (around 25000 watts). On top of that I only charge during off peak hours so even the things like my living room, bathroom, bedroom, kitchen would be running on the minimum. Of course electricians will say you need to get a 200A panel but again I think it depends on the size of your home and also how much additional flexibility you want to additional plugs besides the EVSE.

Just for context, I have a gas dryer, gas water heater and gas stove which would be major users of the electric panel for my condo complex. If more than 1 of these were electric, I would not recommend installing it on a 100A panel.

No basic argument with what you're saying. However, the NEC does specify a Load Calculation that one is supposed to run to determine if there's spare amperage for a heavy load. The web is littered with the calculators. Here's one: Residential Electrical Load Calculation

Now, if one follows that method, far be from me to argue. If not: Suggest that if one didn't follow the tried-and-true method, it might be a good idea to do so. Nice if the numbers came out the same.

 

[Cosmacelf]

I also have a 100A and I did a NEMA 14-50 for my condo complex. What made me decide to do this was because when I filled the local city permit and I had to calculate the total wattage that can be used for a 100A service (48000 watts max), I was far below that (around 25000 watts). On top of that I only charge during off peak hours so even the things like my living room, bathroom, bedroom, kitchen would be running on the minimum. Of course electricians will say you need to get a 200A panel but again I think it depends on the size of your home and also how much additional flexibility you want to additional plugs besides the EVSE.

Just for context, I have a gas dryer, gas water heater and gas stove which would be major users of the electric panel for my condo complex. If more than 1 of these were electric, I would not recommend installing it on a 100A panel.

BTW, you didn't mention how you heat or cool your condo. That's also a major electrical consumer (or can be), and unlike the others, does run at night. But it does sound to me like you had room to add the 14-50.

 

[Eric33432]

I also have a 100A and I did a NEMA 14-50 for my condo complex. What made me decide to do this was because when I filled the local city permit and I had to calculate the total wattage that can be used for a 100A service (48000 watts max), I was far below that (around 25000 watts). On top of that I only charge during off peak hours so even the things like my living room, bathroom, bedroom, kitchen would be running on the minimum. Of course electricians will say you need to get a 200A panel but again I think it depends on the size of your home and also how much additional flexibility you want to additional plugs besides the EVSE.

Just for context, I have a gas dryer, gas water heater and gas stove which would be major users of the electric panel for my condo complex. If more than 1 of these were electric, I would not recommend installing it on a 100A panel.

Don't understand.....100 amp 240 volt service is only 24,000 watts. 100 x 240 = 24,000.

 

[Tronguy]

Don't understand.....100 amp 240 volt service is only 24,000 watts. 100 x 240 = 24,000.

Um. At my place, the line voltage hovers around 250 VAC, 125V on each hot. YMMV.

 

[Eric33432]

Um. At my place, the line voltage hovers around 250 VAC, 125V on each hot. YMMV.

Well, then, you would get 25,000 watts at 100 amps at 250 volts.

 

[davewill]

BTW, you didn't mention how you heat or cool your condo. That's also a major electrical consumer (or can be), and unlike the others, does run at night. But it does sound to me like you had room to add the 14-50.

If he got a permit and passed inspection, the load calc must have worked out. Indeed, you'd have to be an absolute fool to cut corners in a multi-family building.

 

[flai54]

BTW, you didn't mention how you heat or cool your condo. That's also a major electrical consumer (or can be), and unlike the others, does run at night. But it does sound to me like you had room to add the 14-50.

Yes I have central AC available but I don't use it most of the time even though I have a smart thermostat. I live alone and with the crazy electrical costs, I don't need it to run on all night. I only use it in the summer when it is only on hot summer days and never over night. It is just on to keep my room cool and I have a fan running all night. If it is warm, I try to use a blower fan in the living room and when I am up in my room at night, I use one of those portable tube window AC units since I don't need the whole house to be cool.