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Quick question about wire gauge size.

jedi713

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My CSP should arrive tomorrow so I am trying to plan out what all I need to buy. I already have a 100 amp sub panel in my garage that is for my wood working tools. I have a bunch of left over 3/4 EMT from a previous project. Based on both of those factors I was planning on using a 60amp breaker to power the CSP (derating it to 48amp). The run will be ~38 feet in total. I thought I had read another thread here that #6THHN would be sufficient for both hots in this scenario. I can't find the original thread I saw that in so is that correct? Was also planning on running the same size ground, unless smaller is sufficient in this scenario.

In theory the panel could support an 80amp breaker (assuming I am not charging and using tools at the same time), but I thought the increased wire size wouldn't work in my 3/4 EMT, is that correct?

Thanks all.
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Monkey

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#6 AWG THHN is perfect for a 60A circuit (48A sustained load). And yes, needs to be in EMT or MC cable. You can use a smaller gauge wire for the ground -- but not much smaller, like 8 AWG.

Yes, you could install an 80A breaker in the 100A sub panel . And no, you won't be able to run the necessary wire through your 3/4 EMT.
 
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bmwhitetx

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Here is a site I have used: https://www.cerrowire.com/products/resources/tables-calculators/ampacity-charts/
I also run my FCSP derated to 48A on a 60A breaker. THHN #6 is good for a 60A breaker (#6 Romex is not). This site also has a raceway (AKA conduit) fill calculator. I put (2) #6 and a #8 ground in 3/4" conduit. It can be tough pulling if you have many bends, I just assembled the bends and pulled cable as I went.

Here's a pinned thread on the subject https://www.f150lightningforum.com/...a-outlet-to-charge-your-ev.12739/#post-269923
 

jimfigler

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Mike Holt makes a great app , Mike Holt’s Electrical Toolbox
 

davehu

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My CSP should arrive tomorrow so I am trying to plan out what all I need to buy. I already have a 100 amp sub panel in my garage that is for my wood working tools. I have a bunch of left over 3/4 EMT from a previous project. Based on both of those factors I was planning on using a 60amp breaker to power the CSP (derating it to 48amp). The run will be ~38 feet in total. I thought I had read another thread here that #6THHN would be sufficient for both hots in this scenario. I can't find the original thread I saw that in so is that correct? Was also planning on running the same size ground, unless smaller is sufficient in this scenario.

In theory the panel could support an 80amp breaker (assuming I am not charging and using tools at the same time), but I thought the increased wire size wouldn't work in my 3/4 EMT, is that correct?

Thanks all.
the installation manual should have all info you need:
Installation Manual
 

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jedi713

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the installation manual should have all info you need:
Installation Manual
I had looked at the manual a while ago, but didn't see where they had wire recommendations for anything other than 80amp.

Thanks for all of the replies. I just need it to get here so I can figure out the final placement and start running the EMT.
 

davehu

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studying all ths myself as I'm 6 weeks out from getting mine. My electrician said 3g wire for the full 80amp capability although I'll probably limit it to 48a. BTY, you senario is the same as mine: I'm a woodworker and woodturner too and have 100a service to my shop where my CSS power will come from. will not be using the lathe or saw
 
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jedi713

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studying all ths myself as I'm 6 weeks out from getting mine. My electrician said 3g wire for the full 80amp capability although I'll probably limit it to 48a. BTY, you senario is the same as mine: I'm a woodworker and woodturner too and have 100a service to my shop where my CSS power will come from. will not be using the lathe or saw
I'm kind of shocked the electrician said he could put a 100 amp breaker in the panel. I was always under the impression that you shouldn't put the same size breakers behind each other. At some point I saw a chart on charging times, and for my use cases, running at 48a is sufficient (plus I don't have to buy more EMT :) )
 

tls

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#6 AWG THHN is perfect for a 60A circuit (48A sustained load). And yes, needs to be in EMT or MC cable. You can use a smaller gauge wire for the ground -- but not much smaller, like 8 AWG.

Yes, you could install an 80A breaker in the 100A sub panel . And no, you won't be able to run the necessary wire through your 3/4 EMT.
Two #4 will fit in 3/4 EMT and the conduit itself is the ground if it's EMT from end to end, so how does an 80A circuit not fit?
 

Maquis

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I'm kind of shocked the electrician said he could put a 100 amp breaker in the panel. I was always under the impression that you shouldn't put the same size breakers behind each other.
Nothing wrong with that.
 

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khatch

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I'm kind of shocked the electrician said he could put a 100 amp breaker in the panel. I was always under the impression that you shouldn't put the same size breakers behind each other. At some point I saw a chart on charging times, and for my use cases, running at 48a is sufficient (plus I don't have to buy more EMT :) )
shocked? haha
 
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jedi713

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shocked? haha
You see what I did there? I guess my previous electrician was just super cautious when they said it wasn't a good idea.

Either way for me it is a moot point since 3/4 EMT is my limiting factor (unless the EMT fairy shows up with 40ft and a bender).
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