#4 or #6 Cable for 60A circuit
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DevinL
Well-known member
My 60A feeder line for my EVSEs uses #6 wire. My 40A split uses #8, and my 20A split uses #12. As specified by the late great William Korthof of Sustainable Solutions and signed off on by LADWP.
n3ckf
Well-known member
National Electrical CodeTable 310-16 specifies the Ampacity (current carrying capability) of wires by size
Note that the ampacity varies by *temperature* and that is relevant to what type of insulation your wire has.
For instance the most common kind of wire is type THHN (this is what they sell at Home Depot).
So for type THHN rated at 90C (a common rating), size AWG6 Copper wire has an ampcity of 75.
Also per NEC, you must use no more than 80% of the ampacity rating of the wire.
80% of 75 = 60 amps. so #6 THHN wire may be used assuming the rest of the circuit can maintain a temperature of 90C (194F). Thats awfully hot for a non-commerical installation.
That's what "legal". Many electricians will only use #6 wire up to 50 amps as a rule. (and if you're using a different kind of wire, or want a rating at 75degrees C only), you need to go to #4.
If it were me wiring the circuit, i'd spend the extra money and use #4.
Note that the ampacity varies by *temperature* and that is relevant to what type of insulation your wire has.
For instance the most common kind of wire is type THHN (this is what they sell at Home Depot).
So for type THHN rated at 90C (a common rating), size AWG6 Copper wire has an ampcity of 75.
Also per NEC, you must use no more than 80% of the ampacity rating of the wire.
80% of 75 = 60 amps. so #6 THHN wire may be used assuming the rest of the circuit can maintain a temperature of 90C (194F). Thats awfully hot for a non-commerical installation.
That's what "legal". Many electricians will only use #6 wire up to 50 amps as a rule. (and if you're using a different kind of wire, or want a rating at 75degrees C only), you need to go to #4.
If it were me wiring the circuit, i'd spend the extra money and use #4.
Thanks all! This is what I ended up buying: 6-3 Indoor Non-Metallic Jacket Wire (By-the-Foot)
http://www.lowes.com/pd_70166-295-63950045_4294857952_4294937087_
The run is 6-8 ft (bought 9 ft just in case). My install is back to back with my main breaker panel outside to my indoor garage.
Do you guys see any issues with this?
http://www.lowes.com/pd_70166-295-63950045_4294857952_4294937087_
The run is 6-8 ft (bought 9 ft just in case). My install is back to back with my main breaker panel outside to my indoor garage.
Do you guys see any issues with this?
miimura
Well-known member
That jacketed wire must be completely inside the wall, not left exposed. Also, the temperature rating for that type is less than THHN wire in conduit. People say 8 gauge NMB (the type referenced above) is not good enough for a NEMA 14-50, it should be 6 gauge, but my electrician installed it and my inspector passed it during new construction. Similar situation for 6ga vs. 4ga at 60A.
Luckyduckie
Well-known member
The electrician who installed my 32A Aerovironment EVSE told me that it was ok to have #8 THHN in conduit for NEMA 14-50 with a 50A breaker. I might be getting the juicebox; should I go for the 40A or just stick to 32A to be safe??
miimura
Well-known member
You are fine to go 40A with your wiring. Metal conduit will dissipate heat and THHN insulation has a higher temp rating.Luckyduckie said:
Bassman
Well-known member
I have the HCS -60. It only draws 48 amps continuous max. Went with #6 THHN. Has been working for a year and a half with no issues.
I just installed my hcs-60. I had Romex with #6 wire from panel to 14-50outlet on 50amp breaker.(since rav4ev only pull upto 40amp). the hcs-60 comes with #8 wire for both input cord and output cord. (I had added a 14-50 male plug on it.) So I assume #6 for my receptacle should be OK. So far I am charging my rav4ev without issue.
miimura
Well-known member
If you leave the 50A breaker it is sure to be safe. If you only charge vehicles like the RAV that only pull up to 40A you will never have any problem. If you plug in a Model S that has dual chargers, it may pop the breaker after a while - maybe 30 minutes or so. Personally, with #6 Romex (NMB type) I would leave the 50A breaker and not increase it to 60.Rav4EVoom said:
Rav4EVoom said:
I wanted to do the exact same thing, but Clipper Creek explicitly advised against doing so.. They said they required a 60A circuit (and breaker) for the HCS-60. Glad to hear it's working just fine though, but thought I'd let you know CC's stance on it..
49erRAV said:
Thanks for your comment. If you will charge a vehicle that pull more than 40Amp, then using 50Amp breaker will likely trip it. Clipper Creek HCS-60 is designed to output up to 48Amp continuous. So if you indeed pull 48Amp when charging vehicle, you definitely need 60Amp breaker to prevent it from tripping. But if you only charge vehicle that pull Less than or equal to 40Amp, the 50Amp breaker work fine. As far as I know at the present time, only Tesla can pull more than 40Amp when charging. so 50Amp breaker on HCS-60 will work for most other EV.
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