Electrician wants to put in a Disconnect for the FCSP

[jt253035]

I have a 125ft run of copper for the FCSP being ran. There is about 90ft to get to the attached garage and the rest to where the charger is being placed. Electrician says it’s a national electrical code to put in a disconnect on the entry into the garage because it’s going to be rated at 100amps. He said he could do that or a panel. Other electricians I have talked too said to go straight from the main panel to the charger, nothing in between. I told them I don’t need something in between that could fail but they are not budging. They said they will make sure it is pulling 80amps at the charger even with the disconnect there. Any opinions on what I should do? They have done this before and been successful.

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[Tony Burgh]

If something happens, do you want to run 90 feet to the circuit breaker panel? Your A/C is probably closer and it has a pull disconnect.

 

[geoff.]

Can't speak to code, but personally think you'd want a way to kill power within your garage. If there was an emergency, running 125ft through the house to throw a breaker is not something I'd want to be doing. I have a very similar run as you're describing, but wanted a sub panel and a 14-50 outlet.

 

[tls]

It depends which code cycle your municipality is on. For recent code cycles, a disconnect is required for any charger over 60A. However, unlike some other disconnects, this one does not have to be within sight. It does have to be "readily accessible", and it has to be lockable - which is probably why it does not have to be within sight, there are numerous exceptions in the code allowing lockable disconnects to be out of sight of the equipment disconnected.​

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It's entirely possible that your local authority won't be willing to consider a breaker in a panel in another building "readily accessible". Some might even cite the "readily accessible" language as if it meant "within sight" which it does not but you won't get far arguing. Put in the disconnect, make sure it's lockable, and make it as obviously accessible as you can.​

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A separate disconnect rated for 80A will cost a few hundred bucks, but a small outdoor-rated breaker panel will cost you about $50 and a 100A breaker to go in it, $75. The padlock hasp built into the panel's enclosure makes it lockable. Code does not require that the electrician run a neutral to a panel that has only 240V circuits in it, but you might want to have him do so anyway, so that you can use the extra spaces for convenience outlets or whatever.​

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Not using a disconnect or panel near the charger could actually cost you money by forcing the use of copper cable all the way back to your main panel. Most chargers' lugs are not rated for connection to aluminum, but the disconnect or panel gives you a safe place to transition from aluminum to copper, and the Al wire will be much cheaper than running copper all the way.​

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625.43 Disconnecting Means. For equipment rated more than 60 amperes or more than 150 volts to ground, the disconnecting means shall be provided and installed in a readily accessible location. The disconnecting means shall be lockable open in accordance with 110.25.​

 

[jt253035]

It depends which code cycle your municipality is on. For recent code cycles, a disconnect is required for any charger over 60A. However, unlike some other disconnects, this one does not have to be within sight. It does have to be "readily accessible", and it has to be lockable - which is probably why it does not have to be within sight, there are numerous exceptions in the code allowing lockable disconnects to be out of sight of the equipment disconnected.​

​

It's entirely possible that your local authority won't be willing to consider a breaker in a panel in another building "readily accessible". Some might even cite the "readily accessible" language as if it meant "within sight" which it does not but you won't get far arguing. Put in the disconnect, make sure it's lockable, and make it as obviously accessible as you can.​

​

A separate disconnect rated for 80A will cost a few hundred bucks, but a small outdoor-rated breaker panel will cost you about $50 and a 100A breaker to go in it, $75. The padlock hasp built into the panel's enclosure makes it lockable. Code does not require that the electrician run a neutral to a panel that has only 240V circuits in it, but you might want to have him do so anyway, so that you can use the extra spaces for convenience outlets or whatever.​

​

Not using a disconnect or panel near the charger could actually cost you money by forcing the use of copper cable all the way back to your main panel. Most chargers' lugs are not rated for connection to aluminum, but the disconnect or panel gives you a safe place to transition from aluminum to copper, and the Al wire will be much cheaper than running copper all the way.​

​

625.43 Disconnecting Means. For equipment rated more than 60 amperes or more than 150 volts to ground, the disconnecting means shall be provided and installed in a readily accessible location. The disconnecting means shall be lockable open in accordance with 110.25.​

So the electrician wanted to run aluminum from the main panel to the disconnect to help with the cost. What gauge wire should it be? Am I going to lose any charging capacity at the FCSP or have my house burn down from using aluminum on that long of a run with continuous amperage load to the disconnect? Will the the aluminum or disconnect slow down my charging?

 

[Tfarrell73]

Aluminum wire or a disconnect won't affect charging speed. Also Aluminum wire should save few dollars on materials

 

[reffahcs]

I have a 125ft run of copper for the FCSP being ran. There is about 90ft to get to the attached garage and the rest to where the charger is being placed. Electrician says it’s a national electrical code to put in a disconnect on the entry into the garage because it’s going to be rated at 100amps. He said he could do that or a panel. Other electricians I have talked too said to go straight from the main panel to the charger, nothing in between. I told them I don’t need something in between that could fail but they are not budging. They said they will make sure it is pulling 80amps at the charger even with the disconnect there. Any opinions on what I should do? They have done this before and been successful.

As soon as I read disconnect and aluminum, first thing I thought of was Tom's video. "Dangerous Disconnect: Tesla Home Charging Problem Analyzed And Corrected"

 

[jerock]

It was the code here to have the disconnect. I'm quite happy that's the case.

 

[Montecarlossfan]

So the electrician wanted to run aluminum from the main panel to the disconnect to help with the cost. What gauge wire should it be? Am I going to lose any charging capacity at the FCSP or have my house burn down from using aluminum on that long of a run with continuous amperage load to the disconnect? Will the the aluminum or disconnect slow down my charging?

Nope not at all, aluminum to the disconnect and copper to the charger since ford says no aluminum , probably more or less to cover themselves and possibly terminals not rated for aluminum expansion and contraction and the risk of loose terminals over time.

I have 2awg SE Aluminum to my disconnect and 2awg copper disconnect to charger . Wire is barely warm to touch even at 3 hours in on a 30-80 charge

Aluminum got a bad name in older homes but guaranteed your service drop is aluminum and will never be an issue.

 

[jt253035]

Nope not at all, aluminum to the disconnect and copper to the charger since ford says no aluminum , probably more or less to cover themselves and possibly terminals not rated for aluminum expansion and contraction and the risk of loose terminals over time.

I have 2awg SE Aluminum to my disconnect and 2awg copper disconnect to charger . Wire is barely warm to touch even at 3 hours in on a 30-80 charge

Aluminum got a bad name in older homes but guaranteed your service drop is aluminum and will never be an issue.

since my run is pretty long, should I be going with 2awg or is 3awg sufficient?

 

[Maquis]

Yes, a disconnect is required.

This has been in the NEC since at least 2017. I ran 95’ of #1 aluminum to the disconnect and a couple feet of #3 copper from there to the FCSP.

#2 aluminum is only rated for 95A.

 

[Montecarlossfan]

since my run is pretty long, should I be going with 2awg or is 3awg sufficient?

If using aluminum I would drop to 2awg , after the disconnect which should be short you can use 2awg copper or 3awg copper. My run is about 40ft of wire to the disconnect in my case.

 

[Pioneer74]

As soon as I read disconnect and aluminum, first thing I thought of was Tom's video. "Dangerous Disconnect: Tesla Home Charging Problem Analyzed And Corrected"

That is not a propor disconnect.

 

[Maquis]

since my run is pretty long, should I be going with 2awg or is 3awg sufficient?

#1 AL or #3 CU.

 

[Pioneer74]

#1 AL or #3 CU.

And to clarify for the OP, the #1 aluminum only goes from your panel to the line side of the disconnect. The copper is required for the terminals on the FCSP and must be used on the load side of the disconnect or the whole circuit.

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