The code requirement is that at only one place in the house are ground and neutral tied together, and that is in the main panel. So that's where it doesn't matter much if they are co-mingled, and it's more of a neat and tidy thing. But everywhere else in the house, in branch circuits, and any subpanels, the ground and neutral must be kept separate.
-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
Wire size for wall charger
- Thread starter bbwex
- Start date
I'm not sure what you mean by a junction box to split for two chargers. My understanding of electrical code is each charger needs a dedicated wiring with a dedicated breaker. You can't have it split into two devices on one circuit. Maybe you could have a switch at a junction box that locked out the other device so only one could be used at a time, but I'd think it would be better to just set this up as a sub panel or do an additional run of wire.
NEC section 625.42 now covers this, that if the equipment is using a load sharing/management function, they can share an incoming supply line. There is a nice page that Enel-X put together showing the code citations for this labeled "For your electrician:"
6 AWG NM-B has 7 strands in each wire while individual 6 AWG THHN mostly comes in 19 strands. 7 strands 6 AWG individual TTHN is atleast 5 times costly than 19 strands per my search. Is there any difference (current, amp, breaker size etc) between 19 strands vs 7 strands for same 6 AWG THHN copper? It might be financially wise to buy NM-B (7 strands), remove outer seathing and use as THHN in conduit.
Don't do that. THHN conductors are labeled and have a 90C rating. Wires inside NM-B are neither.
BTW, at low frequencies (e.g. 60Hz) the number of strands impacts only flexibility, not ampacity.
You can use the automatic load balancing feature. Install a sub panel and then wire each Wall Connector to the sub panel with its own circuit breaker. Depending on your home's electrical service you may be able to add a 100A sub panel but if less than 100A then it is still OK. With the automatic load balancing each Wall Connector could charge at the maximum, i.e. 48 amps but when used together the load would be limited to 80% of the rating for the sub panel, so 80 amps maximum for a 100 amp sub panel. When used at the same time the two Wall Connector units would each be limited to charging at a maximum or 40 amps or any combination that does not exceed 80 amps. (The automatic load balancing requires that the Wall Connector units can access your home WiFi netwwork.)
If you install two Wall Connectors on a 100 amp sub panel without load balancing then each Wall Connector would never be able to individually support charging at more than 40 amps.
Last edited:
Looks like i have a sub panel already and it's rated up to 70a with only 1 extra breaker slot
You should have an electrician review your home's electrical service and determine if there is additional capacity for another circuit.
Regarding the existing 70A subpanel, it may be possible to move some things and switch to space saver circuit breakers to free up a few slots. 240V requires a double pole breaker; not all slots are capable of being used for 240V circuits.
Protection from physical damage is subjective but I (and all inspectors in my area) would count non metallic flex as protection from physical damage.
And you are allowed to use conduit and a sleeve for up to 10ft.
312.5(C) Cables. Where cable is used, each cable shall be secured
to the cabinet, cutout box, or meter socket enclosure.
Exception: Cables with entirely nonmetallic sheaths shall be permitted to
enter the top of a surface-mounted enclosure through one or more
nonflexible raceways not less than 450 mm (18 in.) and not more than
3.0 m (10 ft) in length, provided all of the following conditions are
met:
Hello...new to forum and just read a new discussion,,
After reading all these posts I think I have a good idea of what to do but have a few questions.
My install will be as follows..
60 amp breaker into a GE PowerMark Gold subpanel. I found no double pole GE THQP 60 amp breaker (slim size) anywhere (maybe doesn't exit ?) so I will have to use a THQP one - tight on spaces!
Will run 3 lines of THHN AWG#6 and a #8 ground wire in 1" inside diameter PVC conduit. Subpanel is right above garage so it will run down in the wall into the garage and over the ceiling of the garage to a wall...all in the conduit...total length about 35 feet. Charger (non Tesla) will be hardwired. Is the conduit size appropriate?
Questions: I assume the PVC conduit is okay mounted to garage wall (block) and ceiling (plaster)?
Should I use a metal or pvc box for the wall mount if the charger (unknown yet??) requires a mounting box?
The point where the pvc connects to the subpanel entrance...do I need to physically secure the loose wires coming out of the pvc to the box before terminating them at their respective places? Somewhere I read this was required. Any reason I can't bring the wires up from the bottom in this scenario?
No one appears to mention GFCI breaker in the discussions...I thought it was still required even for hardwired chargers....is this not true if the charger has a true GFCI built in?
Thanks
After reading all these posts I think I have a good idea of what to do but have a few questions.
My install will be as follows..
60 amp breaker into a GE PowerMark Gold subpanel. I found no double pole GE THQP 60 amp breaker (slim size) anywhere (maybe doesn't exit ?) so I will have to use a THQP one - tight on spaces!
Will run 3 lines of THHN AWG#6 and a #8 ground wire in 1" inside diameter PVC conduit. Subpanel is right above garage so it will run down in the wall into the garage and over the ceiling of the garage to a wall...all in the conduit...total length about 35 feet. Charger (non Tesla) will be hardwired. Is the conduit size appropriate?
Questions: I assume the PVC conduit is okay mounted to garage wall (block) and ceiling (plaster)?
Should I use a metal or pvc box for the wall mount if the charger (unknown yet??) requires a mounting box?
The point where the pvc connects to the subpanel entrance...do I need to physically secure the loose wires coming out of the pvc to the box before terminating them at their respective places? Somewhere I read this was required. Any reason I can't bring the wires up from the bottom in this scenario?
No one appears to mention GFCI breaker in the discussions...I thought it was still required even for hardwired chargers....is this not true if the charger has a true GFCI built in?
Thanks
EVer Hopeful
Active Member
I am not sure about the charger that you will use, but for the Tesla charger, you need just two hot wires and ground. Neutral wire is not needed. Double-check that in your setup you need a neutral wire.
And instead of using THHN #6, I would go with THHN #4 (for 60A breaker setup) to slightly reduce the heating of the wire and resistance, so you ll have less voltage drop under the load.
Last edited:
For the hard-wired connection of the Tesla wall connector - you need a regular two-pole breaker. But you said you ll have a different charger, so read the breaker requirements for that charger.
It would work.. I just said that #4 would be better and just a little more expensive than #6.
And by the way NMB #6 is rated at 55A so can't be used for 60A breaker, while THHN #6 rated at 75A and can be used with a 60A breaker
When looking up maximum amperage ratings for a given type, gauge of wire you need to also be sure the maximum temperature rating for amperage spec. For residential applications use the maximum amperage values for either 60C (140F) or 75C (167F) temperatures, not 90C (194F). The 90C (194F) temperature, maximum amperage specs only apply to commercial installations. For residential use No. 6 gauge THHN wire is rated for up to 65 amps at 75C. 75 amps only applies in commercial applications where 90C is the maximum allowed temperature. (Even if the wire is able to handle temperatures up to 90C the other components in the home, i.e. circuit breakers etc. will only be rated for up to 75C.)
Similar threads
