I'm ready to install the required breaker and wiring for future electric charging and wanted to understand the best sizing for wiring and breaker. What is the maximum size breaker for use on a 6/3 copper cable with less then 20ft run from breaker to receptacle. I have seen 50amp breaker for 6/3 wire that would allow 40 amps current to vehicle, can I use 80 amp breaker on #6/3 and provide 64 amp current to vehicle? I'm assuming this would allow quicker charging time to vehicle.
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I would never put an 80 amp breaker on a circuit with 6/3 wire. It would not be safe.
http://www.cerrowire.com/ampacity-charts
My car has a 40 amp charger. The new cars have either a 48 amp charger or a 72 amp charger. It depends on the car if a larger circuit will charge the car faster or not. In my case the answer would be no.
Lots of good information in the home charging FAQ written by FlasherZ.
FAQ: Home Tesla charging infrastructure Q&A
To go higher than 40 Amp charging (50 Amp circuit breaker) you can't use the UMC that comes with your Tesla. You will need to buy the HPWC.
While having the HPWC and keeping the UMC in the car is the ultimate setup, 40 Amp charging is plenty fast enough for overnight charging. Charging faster than that is nice on the road, but is only useful at home in rare situations.
GSP
While having the HPWC and keeping the UMC in the car is the ultimate setup, 40 Amp charging is plenty fast enough for overnight charging. Charging faster than that is nice on the road, but is only useful at home in rare situations.
GSP
A 50 amp breaker is the largest you can put on #6 wire. 40 amps is the largest continuous load you can put on that circuit.
If you want to charge at a higher rate, you'll need bigger wire.
If you want to charge at a higher rate, you'll need bigger wire.
Do not run a #6/3 wire on 80A breaker, drawing 64A. Either upgrade your wiring to #4 or keep the #6 wiring and install the 60A breaker and set your charging current to 48A. You must observe the 80% rule between the breaker size and current draw. Your current draw should be within 80% of the breaker rating.
RAM_Eh
Member
Wrong.
I am an electrician and this entirely depends on the location.
Ontario: Use the proper cable with the right insulation value and you can drive 60A through a number 6 AWG cable. If you use house wire (NMW) you will only get 50A out of it. If you use armoured or teck cable you can get the full 60A. Cable in not de-rated in the Canadian electrical code, Only the breaker.
Not an electrician so verify with someone who is but with anything over 60A(in ontario) I think/believe you also need to put a disconnect near the outlet or charger. Going with the 50A breaker might save the extra disconnect switch unless you really have to charge your car faster
This is not correct. If 6 awg wire is put in conduit instead of using Romex you can use a 60 amp breaker. With the appropriate wall charger you can charge at 48 amps which is 11.5 kw. With Romex you can only have 55 amps. The closest breaker is 50 amps which allows 40 amp charging.
Well said!
CEC Table 19 shows that NMD90 has a maximum allowable conductor temperature of 90C, not 60C like NM-B in the US.
The limiting factor in a house will be the breakers, which are typically 60C/75C rated. The 75C rating for #6 NMD90 cable is 65A.
Like you said, rules are different in different jurisdictions.
I am not an Electrician, just someone who went down the rabbit hole reading the OESC code before having a Licensed Electrician install my wall connector, which was approved by ESA.
Read Bulletin4-13-*, if you have questions about load calculations and are in Ontario, CA. You can use the peak demand ampacity + rated damand ampacity for the last 12 months to determine if you have the capacity in your panel to add your EVSE. This may save you from upgrading a panel, if you don't use much of its capacity.
Interesting. Could you just add a junction box and switch to a higher gauge for the last few feet to the breaker? Probably not the best idea due to voltage drop, but could be a way to eek a bit more out of your feeder wire if you swap out the meter to panel run.
The whole system must be rated to the lowest temperature rating.
What I mean by 60C/75C breaker is that you can use either 60C or 75C ampacity, so 65A is valid.
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