Jhenson29
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- Jeremy
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The below is USA specific.
I'll lead with my question:
Does anyone know what size conductors Clipper Creek uses in their 80 amp J1772 Cable?
Story below:
I purchased an 18kW Wall Wattz (240VAC / 75 A). For hardwiring, it comes with 6 foot of LFNC with 6 AWG THHN wires for connection to a 100-amp breaker.
https://wattzilla.com/products/wall-wattz.htm
I called them today to question the wire size as it seems small. They guy told me it doesn't need to be any bigger because that's the size of the wires in the cable [for the J1772 plug]. He said the 6 AWG is good for 99 amps and the unit is UL tested as is. I can't open it to replace the feed wires without voiding the warranty.
He put me in touch with the principal engineer he worked with at UL. This guy directed me to NEC Table 400.5(B) which shows that 6 AWG is good for 99 amps if it's only two current carrying conductors. Okay. But I have two issues. One I pressed him on and one I didn't.
The first is temperature derating. 400.5(B) is listed at 30°C (86°F). There's no further temperature derating information in 400 so it should default to Table 310.16. I questioned him about ambient temperature and derating with 310.16. Given this is an EVSE and I would expect higher ambient temperatures are a reasonable consideration. He told me all EVSEs should be rated to 50°C (122°F). The Wattzilla guy was still on the line with us and chimed in that they actually have a higher rating, but didn't state what that is. But generally, the UL guy more or less blew me off on this. I went back to check later and going by 50°C, that would put the derating at 0.82. So, it's around 81 amps. It may be okay, but it still seems marginal.
The second issue (that I didn't get to because I didn't think about it at the time) is that Article 400 is for flexible cords and cables, which the LFNC feeding the unit is not. I believe this would just fall under 310.16 (in a raceway with 3 or less current carrying conductors) and then I'm looking at 75 amps for the 6 AWG THHN before temperature derating. It's 61 amps at 50°C. Although, for my area, even in a garage, the next lower temperature range is more reasonable with a derating of 0.87 which is 65 amps.
The second issue is really what I was calling them about because of my concern for the 6 AWG feed wires. The electrician I have quoted running something larger to the unit, but that was before I found out I'm not allowed to open it up. I'm not sure what to do now other than install as is.
I'll lead with my question:
Does anyone know what size conductors Clipper Creek uses in their 80 amp J1772 Cable?
Story below:
I purchased an 18kW Wall Wattz (240VAC / 75 A). For hardwiring, it comes with 6 foot of LFNC with 6 AWG THHN wires for connection to a 100-amp breaker.
https://wattzilla.com/products/wall-wattz.htm
I called them today to question the wire size as it seems small. They guy told me it doesn't need to be any bigger because that's the size of the wires in the cable [for the J1772 plug]. He said the 6 AWG is good for 99 amps and the unit is UL tested as is. I can't open it to replace the feed wires without voiding the warranty.
He put me in touch with the principal engineer he worked with at UL. This guy directed me to NEC Table 400.5(B) which shows that 6 AWG is good for 99 amps if it's only two current carrying conductors. Okay. But I have two issues. One I pressed him on and one I didn't.
The first is temperature derating. 400.5(B) is listed at 30°C (86°F). There's no further temperature derating information in 400 so it should default to Table 310.16. I questioned him about ambient temperature and derating with 310.16. Given this is an EVSE and I would expect higher ambient temperatures are a reasonable consideration. He told me all EVSEs should be rated to 50°C (122°F). The Wattzilla guy was still on the line with us and chimed in that they actually have a higher rating, but didn't state what that is. But generally, the UL guy more or less blew me off on this. I went back to check later and going by 50°C, that would put the derating at 0.82. So, it's around 81 amps. It may be okay, but it still seems marginal.
The second issue (that I didn't get to because I didn't think about it at the time) is that Article 400 is for flexible cords and cables, which the LFNC feeding the unit is not. I believe this would just fall under 310.16 (in a raceway with 3 or less current carrying conductors) and then I'm looking at 75 amps for the 6 AWG THHN before temperature derating. It's 61 amps at 50°C. Although, for my area, even in a garage, the next lower temperature range is more reasonable with a derating of 0.87 which is 65 amps.
The second issue is really what I was calling them about because of my concern for the 6 AWG feed wires. The electrician I have quoted running something larger to the unit, but that was before I found out I'm not allowed to open it up. I'm not sure what to do now other than install as is.
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