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110 amp circuit breaker installation

110 amp circuit breaker installation

I sent an email to tesla about this as well. My office is an old building with outdated electrical system. the best option for me is to connect the tesla charger to an unused 110 amp circuit breaker. The manual says "up to 100 amp" circuit breaker for installation of their charger. I have tried to get a 100 amp circuit breaker for this electrical box and they are no longer made. would it hurt anything to use the 110 amp circuit? thanks for any help on this Mark

campusden | February 1, 2017

Well, where do you live? USA, EUROPE, or Australia?
You have found a 110 Amp breaker but not a 100 Amp breaker?
What brand do you have? Double pole or Single pole?
My intial answer would be "No"
110 on a bkr would usually mean voltage not amperage.

eric.zucker | February 1, 2017

My advice is don't do it yourself if you don't know what you are doing. High current circuits must be wired and connected to a certain spec to avoid fire risk. A loose screw, or insufficiently clean wire creates a resistance point, which will heat up dramatically.

Technically there isn't much risk, as all components have tolerances, and an extra 10 amps should not exceed the safety margin.

What is more troublesome is in case of an issue, this can be used to reduce your insurance coverage (they will use anything to avoid paying the damage).

If you can find an 80A breaker, use that. The car only charges at up to 72A anyway.

The electrical code in my country allows a smaller breaker after a large one. You could add the 80A (or 100A) breaker in a new boy between the main panel and the HPWC to play it safe. Check with your electrician, and let him do the connections. If you want to save money, install the conduit and recommended wiring, let him do the connections.

markmd162 | February 1, 2017

thanks guys. I am definitely going to have an electrician do it. I am in Georgia. I will look to see if I can use an 80 amp switch and move whatever is hooked to theto the 110 amp circuit. I will let you know what tesla says as well. cheers

Vawlkus | February 1, 2017

where the hell do you even GET a 110 amp connection?

Rocky_H | February 1, 2017

In can't picture any company actually making a 110 amp breaker.
I'm going to go with @campusden's idea that someone is mixing up something about "110 volts" with "110 amps".

Solarman004 | February 1, 2017

Looks like they are readily available--
http://fs8.formsite.com/cohealth/form542518383/index.html

Solarman004 | February 1, 2017

Dang forum-- the real link is on Amazon
Cutler Hammer br2110

Solarman004 | February 1, 2017

I'm getting blocked trying to post the links, but I've found a number of 110 amp, 240 V breakers online. But I don't think I've ever seen one in use in a residential breaker box. It does seem like an odd size.

Rocky_H | February 2, 2017

OK, well, let's assume the 110A breaker does exist then.

@markmd, Quote: " would it hurt anything to use the 110 amp circuit? "

Technically...I don't quite know if it would hurt anything, but first off, it's just flat out illegal, since it violates code, so I would NEVER recommend it. If you can't find a 100 or 80 or some reasonable sized breaker that the wall connector is made to support, then you need to replace the old outdated electrical panel with something modern.

Specifically, here is the main problem with what you are suggesting. If you have a circuit that uses wiring and a device rated for a lower current, but then have a higher capacity breaker on it, it is not doing its function. It is called an "overcurrent protection device" in the electric code for a reason. If you have a stove that is rated for 50A, and you use wiring rated for 50A, but put it on an 80A breaker, that breaker isn't protecting anything. If the stove has a wiring problem, partial short/whatever, and it starts drawing 60 or 70 amps, the breaker will be happy and not cut anything off while the wire overheats, melts, and sets your house on fire. That is, what they call in the trade, Bad (TM).

Potentially, if you use oversized wire, so it supports 110A+, that would be safer, and the wall connector can be set to limit itself, but using an oversized breaker is just not a good idea.

psusi | February 2, 2017

Using a 110 amp breaker does not violate code, assuming the wires are rated for it. You are supposed to use one reasonably close to the required load, but 10% over is pretty close.

Rocky_H | February 3, 2017

@psusi, Quote: "Using a 110 amp breaker does not violate code,"

I'm pretty certain that is not true. You have to go by the nameplate rating of the appliance, and the Tesla wall connector says 100A. Electric code does not go by "close enough".

Rocky_H | February 3, 2017

Oh, does not go by either "reasonably close" or "close enough".

biggestfan | February 4, 2017

Using the 110 amp circuit would not "violate code". The 110 amp circuit has a maximum rating of up to 110 amps.

There is nothing wrong with drawing fewer amps than what the circuit is rated for.

If you try to draw more amps than a circuit is rated for, that is when you would run into a problem and either trip your breaker or burn out the fuse depending on whether your electric uses breakers or fuses.

milesbb | February 5, 2017

By code the following breakers are standard sizes NEC 240.6(A)
The standard ampere ratings for fuses and inverse time circuit breakers shall be considered 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 110, 125, 150, 175, 200, 225, 250, 300, 350, 400, 450, 500, 600, 700, 800, 1000, 1200, 1600, 2000, 2500, 3000, 4000, 5000, and 6000 amperes.
Yes 110amps is a standard size.

Using a 110 amp breaker is a code violation. NEC 210.3(B) requires you follow manufactures instructions. Tesla calls out 100 amp max. As stated by @eric.zucker you could install a sub panel with a 100 amp breaker. I believe a 100 amp breaker will be available for your panel. A strong market exists for old and out dated breaker styles. Look harder, even check used breakers, try eBay.

Rocky_H | February 6, 2017

@biggestfan, Quote: "Using the 110 amp circuit would not "violate code". The 110 amp circuit has a maximum rating of up to 110 amps.

There is nothing wrong with drawing fewer amps than what the circuit is rated for.

If you try to draw more amps than a circuit is rated for, that is when you would run into a problem and either trip your breaker or burn out the fuse depending on whether your electric uses breakers or fuses."

Wow. That is blatantly WRONG and really dangerous. Don't EVER give that advice to people. If that were the case, why use any smaller sized breakers. Use 110A breakers for absolutely everything. (I'm being really sarcastic here.)

As @milesbb pointed out, it violates code right off the bat, because code says you have to comply with the installation instructions of the appliance. So since it says you can't use higher than a 100A, you just can't and it's a code violation--open and shut.

But secondly, you are missing what a breaker is supposed to be for. If you have a 30A air conditioner circuit, you can't just say I need a breaker that is at least 30A or greater. It doesn't work that way. If you put a 60 or 100A breaker on it, it's not protecting anything. It will let the current go up much higher(HOTTER) than the appliance/outlet/wiring are designed to handle, and one of them very likely will catch on fire.

Oversizing a breaker is the most dangerous thing you can do. Having the breaker a little undersized still wouldn't be code compliant generally, but at least it's overprotective.

psusi | February 7, 2017

@Rocky_H, like I said, the wires need to be able to handle it but just because the appliance doesn't doesn't need it all does not mean it will cause a problem. You want the breaker as low as you can reasonably get it to get the maximum protection, but it isn't like you are going to have a short that magically draws only 105 amps and so the 100 amp breaker would interrupt it but the 110 won't... in fact, the breakers usually need something like a 10-15% overload before they trip.

What the hell are you supposed to do when you plug your 1 amp light bulb into a standard 20 or 25 amp circuit? Oh noes, you're breaker is 2,000% oversized!

Rocky_H | February 7, 2017

@psusi, Despite your being a smartass, I'll humor your questions. This is still why I like this forum better than TMC, though. It is a little irritating, but still fun to be able to argue like this with some sarcasm, which TMC won't tolerate.

Quote: " it isn't like you are going to have a short that magically draws only 105 amps and so the 100 amp breaker would interrupt it but the 110 won't."

Doesn't have to be anything "magical" about it. There can any type of fault in a device, ranging along a whole spectrum of resistances, where it doesn't have to be and either or of something shorted or not. So yes, it is possible to have 105A from some kind of defect or damage.

Quote: " in fact, the breakers usually need something like a 10-15% overload before they trip."

Yeah, there are curves where it will trip quicker on higher overload and slower on smaller overload.

You did previously say "assuming the wires are rated for it.", so you are at least understanding the necessity of if you were to use a larger breaker, the wiring must go with the breaker rating, not just the appliance rating. That is the biggest concern, which I was not seeing coming from @biggestfan, where it seemed the plan might be to use wire sized for 80 or 100 amp circuit and just use a 110 because it's at least that much or close enough. That was the concerning part.

Quote: "What the hell are you supposed to do when you plug your 1 amp light bulb into a standard 20 or 25 amp circuit? Oh noes, you're breaker is 2,000% oversized!"

Entirely different section of rules in NEC. This is about a 240V circuit, which is to be a dedicated line that is supposed to match its one appliance, not many low power lights and outlets sharing one 120V circuit. And again, the outlet and wiring in the wall are properly sized for the 20A circuit.

TeslaTap.com | February 8, 2017

Rocky +1.

I was going to answer earlier, but you did a far better job than I would have!

Too many people don't understand what kinds of risks they take when they don't understand basic electrical concepts. The code is there to protect you, not to make life difficult!

eric.zucker | February 9, 2017

I would add that the wires of your 1 amp light bulb will handle 15 to 20A current in case of a short circuit long enough to trip the breaker without causing a fire.

If an apparatus uses wire incapable of handling the full load of a standard breaker, it must have an appropriate fuse to protect that circuit. It's not the current draw that is the issue, it the maximum safe current handling we're concerned about.