Disconnect before meter

[Hendrix]

In this case, would we need to isolate the grounded conductor at the meter or at the panel?

 

[pete m.]

From 250.142:

Exception No. 2: It shall be permissible to ground meter
enclosures by connection to the grounded circuit conductor
on the load side of the service disconnect where all of the
following conditions apply:
(1) No service ground-fault protection is installed.
(2) All meter enclosures are located immediately adjacent
to the service disconnecting means.
(3) The size of the grounded circuit conductor is not
smaller than the size specified in Table 250.122 for
equipment grounding conductors.

With that exception, assuming all the conditions can be met, the neutral could still be used for bonding at the meter. The neutral would have to be isolated at the panel.

Pete

 

[hurk27]

At the service disconnect/panel

A meter disconnect is not a service disconnect and is allowed to be ahead of the service disconnect, this is called "cold sequencing" the meter and can be common with some utility's see 230.82(3) also you use the grounded conductor as the bonding anywhere ahead of the service disconnect as this is.

 

[texie]

Here is an idea. http://www.milbankmfg.com/products/catalogs/CatalogFiles/PDF/5764.pdf I know everbody must think I work for Milbank, I just think this is such good idea for those times you need to do cold sequence metering. Seems so simple and clean.

 

[Hendrix]

At the service disconnect/panel

A meter disconnect is not a service disconnect and is allowed to be ahead of the service disconnect, this is called "cold sequencing" the meter and can be common with some utility's see 230.82(3) also you use the grounded conductor as the bonding anywhere ahead of the service disconnect as this is.

I think that 230.82(3) is for 3 phase services. This is single phase.

 

[iwire]

At the service disconnect/panel

A meter disconnect is not a service disconnect and is allowed to be ahead of the service disconnect, this is called "cold sequencing" the meter and can be common with some utility's see 230.82(3) also you use the grounded conductor as the bonding anywhere ahead of the service disconnect as this is.

Just because it is ahead of the meter does not mean it cannot be the service disconnect.

We do a lot of 'cold sequence' metering and the service disconnect and over current protection is ahead of the meter.

However, if you are in an area where the power company takes over control over anything on the supply side of the meter you have to go with a meter disconnect without OCP if you did not do that you would not have access to the over current protection in a service disconnect. (Hope I was clear)

 

[hurk27]

I think that 230.82(3) is for 3 phase services. This is single phase.

I do not see anything in this section that say's it is only for 3-phase?

Just because it is ahead of the meter does not mean it cannot be the service disconnect.

We do a lot of 'cold sequence' metering and the service disconnect and over current protection is ahead of the meter.

However, if you are in an area where the power company takes over control over anything on the supply side of the meter you have to go with a meter disconnect without OCP if you did not do that you would not have access to the over current protection in a service disconnect. (Hope I was clear)

Agreed.

 

[Hendrix]

I was a bit confused by the comentary in the handbook.

 

[texie]

Just because it is ahead of the meter does not mean it cannot be the service disconnect.

We do a lot of 'cold sequence' metering and the service disconnect and over current protection is ahead of the meter.

However, if you are in an area where the power company takes over control over anything on the supply side of the meter you have to go with a meter disconnect without OCP if you did not do that you would not have access to the over current protection in a service disconnect. (Hope I was clear)

Agreed. Many POCO cold sequence rules are that way and you need another service disconnect on the customer side. At first glace it appears that the Milbank product I mentioned earlier can be had with non automatic CB or regular CB to accomodate the application as required.

 

[texie]

Agreed. Many POCO cold sequence rules are that way and you need another service disconnect on the customer side. At first glace it appears that the Milbank product I mentioned earlier can be had with non automatic CB or regular CB to accomodate the application as required.

As a side note, I might add that my sense is that POCO's that use cold sequence and require lockable/sealable swicthes (IE under their control) on their side is to make meter tampering less attractive.

 

[tom baker]

We often install a non fused disconnect ahead of the meter as long as the available AIC is less than 10,000 Amperes (rating of nonfused switches), typically outside. Then we installed a fused disco inside the bldg. The non fused is locked on, and the neutral is bonded there and at the fused disco, which is the NEC required service disconnect. if you have a copy of Mike Holts GVB book there is a picture in it of an installation I did.