Residential Main Breaker Question

[Jimmy7]

Massachusetts has adopted the 2020 Code. Article 230.85 of the 2020 code requires an emergency disconnect on one and two family dwellings that should be located in an outdoor accessible location. I was just asked by a building contractor to replace and relocate a 200 amp underground meter socket. With the new location of the meter socket I wouldn't have to touch the 200 hundred amp panel, just the conductors between the meter socket and the panel. With this new code article I was planning on installing a meter main in order to abide by 230.85. My question is this, do I have to change out the main breaker panel to a main lug only panel? I know the panel will be classified as a subpanel because the service disconnecting means will be outside, so I'll have to separate the neutrals and the grounds. Could you give me your thoughts on this

 

[hillbilly1]

You can have a main in a sub panel, but as you said, the neutral bar will have to be insulated, and the grounds and neutrals separated. No need to change the panel, even if the main breaker in the panel is a higher amp than the service disconnect breaker.

 

[LarryFine]

Agreed. No issue with a redundant second breaker.

 

[kwired]

Whether or not you must use a meter with a main is dependent on other conditions as well as AHJ rules/interpretations.

Strictly going with NEC content and assuming your existing main will still remain near point of entry, I wouldn't think you would be required to put a new disconnect ahead of the existing unless AHJ determines they want this updated per their own rules.

Also keep in mind the wording of this new rule kind of has holes in it for interpretation as well. You could add a non fused switch and still comply with the rule and leave the existing service disconnect as is - if it still meets other service disconnecting means requirements. But since typical meter-main is rated for use as service disconnecting means and there is no specific exemption in new code to allow it to be the emergency disconnect and keep your existing service disconnect as is - some AHJ's are likely to say you have moved the service disconnect and now need to change bonding and grounding accordingly.

As mentioned you don't have to remove the existing main breaker just because it is no longer the service disconnect - it is now just a disconnect on a feeder circuit.

 

[infinity]

You will also need to move the GEC(s) to the meter main.

 

[synchro]

You will also need to move the GEC(s) to the meter main.

Rob,
In doing this do you know if the GEC can route through the existing panel (but not with the service conductors), or does it have to be completely separated from the panel that's now a subpanel? The GEC wiring would, of course, have to be continuous or with irreversible splicing.

 

[don_resqcapt19]

You can install just an "emergency disconnect" that is not the service disconnect and not have to make any other changes. Not sure if there are any "molded case switches" that would fit the meter main, but if there are, that would be one way.

 

[tom baker]

Rob,
In doing this do you know if the GEC can route through the existing panel (but not with the service conductors), or does it have to be completely separated from the panel that's now a subpanel? The GEC wiring would, of course, have to be continuous or with irreversible splicing.

The GEC can route thru the panel and with the service conductors...watch for conduit fill, and max fill for an LB if used, but there are special rules on bonding it, see 250.64(E)

 

[tom baker]

Also keep in mind the wording of this new rule kind of has holes in it for interpretation as well. You could add a non fused switch and still comply with the rule and leave the existing service disconnect as is - if it still meets other service disconnecting means requirements. But since typical meter-main is rated for use as service disconnecting means and there is no specific exemption in new code to allow it to be the emergency disconnect and keep your existing service disconnect as is - some AHJ's are likely to say you have moved the service disconnect and now need to change bonding and grounding accordingly.

I would suspect companies will shortly come up with a meter socket with non fused disconnect, with the appropriate labels. If it was not a "service disconnect" then thats a savings for a retrofit (avoids issues with GEC)

 

[Knuckle Dragger]

I would suspect companies will shortly come up with a meter socket with non fused disconnect, with the appropriate labels. If it was not a "service disconnect" then thats a savings for a retrofit (avoids issues with GEC)

Maybe they should just install a handle on the face of the meter so you could pull it off in one yank?

 

[JoeNorm]

Is there a way to insert a disconnect between a meter and main panel and not have it be considered "first means of disconnect"?

 

[tom baker]

The key is what the language says is required (emergency disconnect) and the NEC terms (service disconnect). Section 230.85 discusses a "disconnecting means", and there are 3 types, line, meter and load. They do not have to be fused, but need to interrupt short circuit current.
There is a definition for disconnecting means, and service equipment.... But service equipment is a CB or fuse and a switch.
Mike Holt once said it takes 3 code cycles to get a rule change correct!

 

[JoeNorm]

So if one was to install a knife-switch disconnect, without overcorrect protection, in-between a meter and main panel we could consider this just a switch, and not have to worry about changing where the ground-neutral bond is located?

 

[tom baker]

Thats the way I see it, and the AHJ would have to realize the what this is and the intent is to disconnect the power in emergencies. A non fused disconnect could be used, if it had the correct AIC (the 480 V SQ Ds I used were 10KAIC, these were disconnects ahead of the meter on 480 Volt services required by POCO. This happened in the early 1980s around here, it took a while to sort it out with the POCO wanting to put there lock on it even if the disconnect had fuses, and for the AHJ to determine the fee schedule - service or feeder)
Would the POCO allow a disconnect ahead of the meter on dwelling units? Probably not due to homeowners being able to turn off power to meter.
I just realized the POCOs are going to need to update there customer service handbooks.

 

[don_resqcapt19]

So if one was to install a knife-switch disconnect, without overcorrect protection, in-between a meter and main panel we could consider this just a switch, and not have to worry about changing where the ground-neutral bond is located?

That is correct.

 

[hillbilly1]

Thats the way I see it, and the AHJ would have to realize the what this is and the intent is to disconnect the power in emergencies. A non fused disconnect could be used, if it had the correct AIC (the 480 V SQ Ds I used were 10KAIC, these were disconnects ahead of the meter on 480 Volt services required by POCO. This happened in the early 1980s around here, it took a while to sort it out with the POCO wanting to put there lock on it even if the disconnect had fuses, and for the AHJ to determine the fee schedule - service or feeder)
Would the POCO allow a disconnect ahead of the meter on dwelling units? Probably not due to homeowners being able to turn off power to meter.
I just realized the POCOs are going to need to update there customer service handbooks.

We have that here for certain poco’s. Called cold sequence metering. The 400 amp 480 volt meters are bolt in, so this allows the meter man to turn power off to remove/install the meter without having to turn off power to all of the meters in the group.

 

[kwired]

Thats the way I see it, and the AHJ would have to realize the what this is and the intent is to disconnect the power in emergencies. A non fused disconnect could be used, if it had the correct AIC (the 480 V SQ Ds I used were 10KAIC, these were disconnects ahead of the meter on 480 Volt services required by POCO. This happened in the early 1980s around here, it took a while to sort it out with the POCO wanting to put there lock on it even if the disconnect had fuses, and for the AHJ to determine the fee schedule - service or feeder)
Would the POCO allow a disconnect ahead of the meter on dwelling units? Probably not due to homeowners being able to turn off power to meter.
I just realized the POCOs are going to need to update there customer service handbooks.

When I have seen disconnect on supply side of meter, other than in a meter center, the POCO usually has a lock on both the disconnect door as well as the operating handle. It is there for them to use when they intend to remove the meter and they don't want customer access to unmetered conductors.

 

[GoldDigger]

So, unless a frangible shackle lock is used, it could not serve as an emergency disconnect.

Sent from my XT1585 using Tapatalk

 

[sparky1118]

Massachusetts has adopted the 2020 Code. Article 230.85 of the 2020 code requires an emergency disconnect on one and two family dwellings that should be located in an outdoor accessible location. I was just asked by a building contractor to replace and relocate a 200 amp underground meter socket. With the new location of the meter socket I wouldn't have to touch the 200 hundred amp panel, just the conductors between the meter socket and the panel. With this new code article I was planning on installing a meter main in order to abide by 230.85. My question is this, do I have to change out the main breaker panel to a main lug only panel? I know the panel will be classified as a subpanel because the service disconnecting means will be outside, so I'll have to separate the neutrals and the grounds. Could you give me your thoughts on this

Leave the breaker in the panel as a service disco. Unless you want the added work of changing it all up.

 

[don_resqcapt19]

So, unless a frangible shackle lock is used, it could not serve as an emergency disconnect.

Sent from my XT1585 using Tapatalk

It is still readily accessible per the definition if it has a standard lock. As far as I know, there is no code restriction on placing a lock on the operationg handle of the emergency disconnect.