Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

100 AMP electrical service in home, should I install Wall Connector Gen3?

This site may earn commission on affiliate links.
Another less scientific way to approach this if you have an unknown capacity to add current draw:

10 Run a new 60a circuit with appropriately sized wire and breaker to your garage.
20 Install HPWC and commission at 60a.
30 Start charging.
40 If you trip the main breaker, reset it and lower the amperage on the HPWC to the next level down and go to 30. Else, go to 50.
50 End.
 
  • Disagree
Reactions: MacO512 and Rocky_H
Another less scientific way to approach this if you have an unknown capacity to add current draw:

10 Run a new 60a circuit with appropriately sized wire and breaker to your garage.
20 Install HPWC and commission at 60a.
30 Start charging.
40 If you trip the main breaker, reset it and lower the amperage on the HPWC to the next level down and go to 30. Else, go to 50.
50 End.

This does not sound like a good idea to me;
1 Breakers don't always trip exactly at their limit, they may still function a bit above the limit for a long period of time, but it could damage wiring. This is a similar concept to the 80% rule.
2 This leaves no room for the times power draw is a bit higher (unusual weather, party in the house, etc)
 
Put it in and see what happens, worst case scenario is you pop the breaker so you dial the WC down a bit.

That being said I have a rather large home. Pool 2hp pump (propane heat), Spa with electric heat, 4 ton heat pump, dual electric water heaters, (60g and 40g) dual ovens, 50a induction stove top, 2 large refrigerators and a large stand alone freezer, washer, dryer, salt water aquarium, baseboard electric heaters in the basement, garage and outdoor shed. Too many lights to count that are mostly all on every night as I have a smart home configuration controlling them all. (100% led) 2 WC's on a single 60a breaker, load sharing enabled. Have a 200a entrance and never had to reset a main breaker/fuse in 29 years.

Here is the odd thing, have a whole house backup generator which is only rated at 20kw with a 100a main breaker and a whole house 200a automatic transfer switch. Entire house runs fine off of it including pool, spa and AC. We do not start doing laundry when the gen is running or charge the cars however we do not shut off any breakers to accommodate the reduced electrical input to the home, life goes on as normal running the dishwasher watching TV and internet, once again never an issue. I can tell when the heat pump (65a breaker) kicks in as there is a noticeable dimming of the lights during the initial start up which only lasts a couple of seconds at best. We have had several bad thunder storms this year causing outages and the generator has run at least 48hrs in total in the last couple of months, actually ran yesterday from 2pm to 8pm.

Point is, if one were to calculate the theoretical load there is no way my home should function without popping a breaker here and there.
 
Put it in and see what happens, worst case scenario is you pop the breaker so you dial the WC down a bit.

That being said I have a rather large home. Pool 2hp pump (propane heat), Spa with electric heat, 4 ton heat pump, dual electric water heaters, (60g and 40g) dual ovens, 50a induction stove top, 2 large refrigerators and a large stand alone freezer, washer, dryer, salt water aquarium, baseboard electric heaters in the basement, garage and outdoor shed. Too many lights to count that are mostly all on every night as I have a smart home configuration controlling them all. (100% led) 2 WC's on a single 60a breaker, load sharing enabled. Have a 200a entrance and never had to reset a main breaker/fuse in 29 years.

Here is the odd thing, have a whole house backup generator which is only rated at 20kw with a 100a main breaker and a whole house 200a automatic transfer switch. Entire house runs fine off of it including pool, spa and AC. We do not start doing laundry when the gen is running or charge the cars however we do not shut off any breakers to accommodate the reduced electrical input to the home, life goes on as normal running the dishwasher watching TV and internet, once again never an issue. I can tell when the heat pump (65a breaker) kicks in as there is a noticeable dimming of the lights during the initial start up which only lasts a couple of seconds at best. We have had several bad thunder storms this year causing outages and the generator has run at least 48hrs in total in the last couple of months, actually ran yesterday from 2pm to 8pm.

Point is, if one were to calculate the theoretical load there is no way my home should function without popping a breaker here and there.

Has a licensed electrician added all of these circuits? Have they all been permitted?

If there was ever an electrical fire I'd think you have a very high risk insurance would deny a claim if your load calcs show there is as you say no way your home should function.

Regardless, one house could work fine for many decades with such a setup, that doesn't mean its a good practice for anyone else to emulate.
 
This does not sound like a good idea to me;
1 Breakers don't always trip exactly at their limit, they may still function a bit above the limit for a long period of time, but it could damage wiring. This is a similar concept to the 80% rule.
2 This leaves no room for the times power draw is a bit higher (unusual weather, party in the house, etc)
1 - Line 10 indicates that the breaker and wire for the charging circuit have been appropriately sized. If you suspect that the main service wire and breaker are not appropriately sized, charging is the least of your worries and you probably need to rethink all other electrical usage in your home.

2 - Sure it does. You are just still at line 40. No time constraint was put on this.
 
What seems to be the issue? A dryer typically draws 30amps and a wall connector maxed out is 48, still have 22a left over before popping a breaker assuming he is running the dryer at the same time. Lights, tv and other small stuff is fairly negligible so I see no problem. If ever there is a problem, you can always dial the wall connector down a bit to suit.
A dryer doesn't typically draw 30A. I measured mine at something like 23A when the heating element is on, and it isn't a continuous load either. It cycles on and off.
 
I assume you have something similar.
Maybe today however not back in 1994 when the house was built. If I have an electrician come in and do work, there are no special electrical permits required and no inspections either. I guess the receipt is enough in case of some major failure. Just cannot compare rules and laws from one country to the next or even between provinces or states as there are way too many variables, sometimes even local. Both my wall connectors are set up on 60a breakers with 6 gauge Romex which everyone (in the US) says is not adequate. Our 6 gauge Romex under Canadian standards is rated at 75amps though. Sometimes things make little sense.
 
Maybe today however not back in 1994 when the house was built. If I have an electrician come in and do work, there are no special electrical permits required and no inspections either. I guess the receipt is enough in case of some major failure. Just cannot compare rules and laws from one country to the next or even between provinces or states as there are way too many variables, sometimes even local. Both my wall connectors are set up on 60a breakers with 6 gauge Romex which everyone (in the US) says is not adequate. Our 6 gauge Romex under Canadian standards is rated at 75amps though. Sometimes things make little sense.
NMD90 in Canada is not the same as NM-B in The US. You can only use 75A on 90C circuits (which are not found in homes). So, while still adequate, you can run 65a on 75C circuits.

I don’t know how Quebec works or even where in Canada the Op is from, but in Ontario we have the ESA that inspects electrical installations and upgrades.

Also, if the Op is in Ontario, they can use the ESA bulletin on EVSE installations on existing homes to use a Peak demand ampacity analysis from the last year to determine whether or not they have enough capacity to add the full draw. No need to guess.

Either way, make sure it’s wired to full capacity.

As always, Electrical Contractors know all this stuff and will steer you in the right direction.
 
  • Informative
Reactions: Rocky_H
Maybe today however not back in 1994 when the house was built. If I have an electrician come in and do work, there are no special electrical permits required and no inspections either. I guess the receipt is enough in case of some major failure. Just cannot compare rules and laws from one country to the next or even between provinces or states as there are way too many variables, sometimes even local. Both my wall connectors are set up on 60a breakers with 6 gauge Romex which everyone (in the US) says is not adequate. Our 6 gauge Romex under Canadian standards is rated at 75amps though. Sometimes things make little sense.
Regarding the 75 amp #6 Romex, I wonder if its a climate thing. In Canada, I assume they don't have to plan for the potential for 100F+ ambient temperatures for days on end, and its far too complex(somewhat sarcastic there) to have two different ratings for the same cable based on where in the US its being installed. There is definitely a temperature table for derating and even uprating cables based on ambient temperatures, but I suspect it is almost never consulted.
 
Regarding the 75 amp #6 Romex, I wonder if its a climate thing. In Canada, I assume they don't have to plan for the potential for 100F+ ambient temperatures for days on end, and its far too complex(somewhat sarcastic there) to have two different ratings for the same cable based on where in the US its being installed. There is definitely a temperature table for derating and even uprating cables based on ambient temperatures, but I suspect it is almost never consulted.
Could be. That is done with 14, 12, and 10 awg cable up here.
 
Here is an ampacity chart for NMD-90, in the US you only have NMB-90 which the only difference I can think of is maybe the insulation. Both use a 6 gauge copper wire which obviously can safely carry 75 amps. https://ecat.eleknet.com/PIM_Docs/Docs/STEP_ASSETS_PDF/13560567.pdf
In the US you cannot use the 90C ampacity rating for wire for residential applications. Residential electrical components (circuit breakers, receptacles, terminals) are only rated for a maximum of 75C. It does not matter that the NMD-90 6 gauge wire is rated for 75 amps at 90C as everything else in the home's wiring is only rated for operation at up to 75C.
 
  • Informative
  • Like
Reactions: Rocky_H and MattM24
In the US you cannot use the 90C ampacity rating for wire for residential applications. Residential electrical components (circuit breakers, receptacles, terminals) are only rated for a maximum of 75C. It does not matter that the NMD-90 6 gauge wire is rated for 75 amps at 90C as everything else in the home's wiring is only rated for operation at up to 75C.
The answer I believe is in the insulation which is more robust on the NMD-90 VS NMB-90. Just like 6 gauge THHN can be used in the US @ 90C and rated @ 75A which I believe is the go to wire being used by most on this forum in the US.
 
The answer I believe is in the insulation which is more robust on the NMD-90 VS NMB-90. Just like 6 gauge THHN can be used in the US @ 90C and rated @ 75A which I believe is the go to wire being used by most on this forum in the US.
Residential breakers are 60C/75C rated, so the 90C rating is only useful for derating and cannot go above the 75C rating of 65A in the case of 6awg NMD90 or T90 or R90.
 
  • Informative
Reactions: Rocky_H and jcanoe