NEC 2020 Emergency Disconnect Wiring

[Eli-Bothell]

I'm starting a new construction single-family residence, I know with the 2020 NEC they require an emergency disconnect on the exterior of the home. My confusion is do I treat the emergency disconnect as the main disconnect, and the main breaker panel would be wired like a subpanel with separate ground and neutral bars?

For example the service two hots and neutral into emergency disconnect, connections made and service entrance cable ran through wall to main panel. The question is on the emergency disconnect do I bond the neutral bar to the enclosure and attach the ground electrode wire to the bonded bar? Then the main panel indoors would be treated with separate ground and neutral bars, like a subpanel? The ground between the indoor main panel, and outdoor emergency disconnect would then be bonded at the underground electrode connection. Let me know if this is confusing and I can sketch what I'm referring to, or if someone has a typical diagram with the emergency disconnect that would be helpful. Thank you

 

[Lister1987]

I'm starting a new construction single-family residence, I know with the 2020 NEC they require an emergency disconnect on the exterior of the home. My confusion is do I treat the emergency disconnect as the main disconnect, and the main breaker panel would be wired like a subpanel with separate ground and neutral bars?

For example the service two hots and neutral into emergency disconnect, connections made and service entrance cable ran through wall to main panel. The question is on the emergency disconnect do I bond the neutral bar to the enclosure and attach the ground electrode wire to the bonded bar? Then the main panel indoors would be treated with separate ground and neutral bars, like a subpanel? The ground between the indoor main panel, and outdoor emergency disconnect would then be bonded at the underground electrode connection. Let me know if this is confusing and I can sketch what I'm referring to, or if someone has a typical diagram with the emergency disconnect that would be helpful. Thank you

I can't claim to know the code but think about the intended purpose of the Emergency Disconnect; To remove ALL sources of power from the installation and so it would be prudent to treat as the MAIN disconnect.

If you have multiple sources of power; public utility, private generator, solar, then you'll want to ensure these also go through this disconnect so that 1 operation kills everything.

@Megawatt may be able to better advise.

 

[pc1966]

If you have multiple sources of power; public utility, private generator, solar, then you'll want to ensure these also go through this disconnect so that 1 operation kills everything.

The supply disconnector mentioned here might be something akin to our cut-out so it is purely for the mains coming in just after the billing meter.

I agree though if they have backup power from generator/solar+battery/etc then having a single means of safe disconnection for everything further down from change-over switches is a very good idea.

@Megawatt may be able to better advise.

Definitely!

 

[pc1966]

Let me know if this is confusing and I can sketch what I'm referring to, or if someone has a typical diagram with the emergency disconnect that would be helpful. Thank you

That might be helpful.

Many of the folks on here are UK-based so very different rules to the NEC, but we still see what is going on over the pond as interesting.

 

[Eli-Bothell]

Okay, so the thought would be the main supply source with neutral goes in and through the disconnect. Neutral is bonded to the enclosure, no need to add a ground to the neutral bar?

 

[Megawatt]

I'm starting a new construction single-family residence, I know with the 2020 NEC they require an emergency disconnect on the exterior of the home. My confusion is do I treat the emergency disconnect as the main disconnect, and the main breaker panel would be wired like a subpanel with separate ground and neutral bars?

For example the service two hots and neutral into emergency disconnect, connections made and service entrance cable ran through wall to main panel. The question is on the emergency disconnect do I bond the neutral bar to the enclosure and attach the ground electrode wire to the bonded bar? Then the main panel indoors would be treated with separate ground and neutral bars, like a subpanel? The ground between the indoor main panel, and outdoor emergency disconnect would then be bonded at the underground electrode connection. Let me know if this is confusing and I can sketch what I'm referring to, or if someone has a typical diagram with the emergency disconnect that would be helpful. Thank you

By definition of the NEC says that the first panel or disconnect after the transformer shall be bonded with a minimum of 2 electrodes to earth. Instead of having just a disconnect why don’t you install a main panel outside with a main breaker and do all your bonding there. Then your house panel will require that all grounds and neutrals shall be kept separate.