250.32

[A/A Fuel GTX]

Would 250.32 Exception allow me to convert existing service entrance conductors into a feeder without installing a grounding conductor? I say "yes" but as always I like to have my assumptions verified.

 

[augie47]

I'm afraid I'd say "no" as I feel from the wording that 250.32 applies to feeders and branch circuits to SEPARATE buildings or structures.

 

[A/A Fuel GTX]

I'm afraid I'd say "no" as I feel from the wording that 250.32 applies to feeders and branch circuits to SEPARATE buildings or structures.

Augie, I have a dwelling where the overhead service entrance conductors originate from a service point at a pole in the middle of the yard. I plan on upgrading the service with a new 200A meter socket and feed thru panel, keeping the service point at that pole. If I connect the existing service entrance conductors to the feed thru panel, they become feeders and not service entrance conductors anymore. Thus my logic in citing 250.32.

 

[augie47]

I would say, in that situation, you stand on solid ground using the exception. Now if your AHJ only agrees

 

[Dennis Alwon]

I would definitely run that by an AHJ since you have now made the service conductors feeders. I am not sure that is the purpose or intent of 250.32 but heck- go for it.

 

[LarryFine]

It's 250.32(B)(2) that permits this (in '05, not in '08). The only exception I see is to 250.32(A), which only applies to BC's, not feeders.

Added: Aha. I see that, in '08, they changed (2) into an exception.

 

[jxofaltrds]

Would 250.32 Exception allow me to convert existing service entrance conductors into a feeder without installing a grounding conductor? I say "yes" but as always I like to have my assumptions verified.

I say no. You are using an exception for existing premises wiring then saying that you are changing the conditions of this existing premisis wiring.

Am I correct on what you are saying?

 

[A/A Fuel GTX]

I say no. You are using an exception for existing premises wiring then saying that you are changing the conditions of this existing premisis wiring.

Am I correct on what you are saying?

What I'm saying is that I would like to change a 3 wire service entrance to a 3 wire feeder. There are no parallel paths involved. Prior to '08, it was legal to install a three wire feeder provided there were no parallel paths. IMO, the exception in 250.32 would allow this since this is an existing installation. I've got a farm with a meter at the service point in the middle of the property. From the service point, there is an overhead drop to the house. I want to upgrade the service point with a new meter and feed thru panel so I can service several buildings on the property with 4 wire feeders. The HO doesn't want to change the drop going to the house. Therefore, if I energize the drop to the house from the feed thru panel, it becomes a feeder. My other thought was to put in a 320A socket, double lug the load side and feed the house and the panel at the service point from the larger meter socket keeping the service entrance conductors as they are.

 

[Smart $]

IMO, you would be compliant.

I don't believe it matters that the original conductors were service entrance. The base qualification is the conductors are of a premises wiring system which existed prior whatever change is taking place, and will again supply the building or structure, subject to the additional requirements.

 

[hornetd]

What is the homeowners objection to your changing the drop to four wire quadplex or equivalent? If it is just the additional cost then he/she is being penny wise and pound foolish. If there are any livestock on that farm they are begging for stray current problems by using a three wire feeder. Stray currents can cost thousands of dollars in livestock production. Many years ago I was on a dairy wiring job when I noticed a cow trying to sneak up on her water cup. The poor thing was getting a shock due to stray current each time she tried to drink. Once I converted all of the feeders to four wire and got the utility to put in an isolation transformer production went up sharply. It took me a while to find and clear all of the old work that had been bonded to the neutral but once I did the only remaining stray current was coming from off premise. When I showed the Public Utilities Commission engineer the Amprobe clamp on current reading of the current flowing on the main bonding jumper with the service equipment open he ordered the utility to clear up the problem within seventy two hours. They installed an isolation transformer to separate the farms neutrals from the Multi Grounded Neutral of their distribution system. If we hadn't cleaned up the farms wiring first the utility would have claimed that the stray current was coming from the farms outdated wiring system.

 

[A/A Fuel GTX]

What is the homeowners objection to your changing the drop to four wire quadplex or equivalent? If it is just the additional cost then he/she is being penny wise and pound foolish. If there are any livestock on that farm they are begging for stray current problems by using a three wire feeder. Stray currents can cost thousands of dollars in livestock production. Many years ago I was on a dairy wiring job when I noticed a cow trying to sneak up on her water cup. The poor thing was getting a shock due to stray current each time she tried to drink. Once I converted all of the feeders to four wire and got the utility to put in an isolation transformer production went up sharply. It took me a while to find and clear all of the old work that had been bonded to the neutral but once I did the only remaining stray current was coming from off premise. When I showed the Public Utilities Commission engineer the Amprobe clamp on current reading of the current flowing on the main bonding jumper with the service equipment open he ordered the utility to clear up the problem within seventy two hours. They installed an isolation transformer to separate the farms neutrals from the Multi Grounded Neutral of their distribution system. If we hadn't cleaned up the farms wiring first the utility would have claimed that the stray current was coming from the farms outdated wiring system.

Excellent point and I agree with you. This is an inactive farm with just a couple of horses running around. As far as the HO goes......You can lead a horse to water..........

 

[kwired]

The pole and the house are separate structures why is there a problem with allowing the exception. It is no different than if you were doing the same with a line between the house and another outbuilding that only originally had a three wire feeder.

If mother nature took the pole down and destroyed the equipment on it you likely would replace it in a similar fashion and not question it much if at all.

 

[augie47]

The pole and the house are separate structures why is there a problem with allowing the exception. It is no different than if you were doing the same with a line between the house and another outbuilding that only originally had a three wire feeder.

If mother nature took the pole down and destroyed the equipment on it you likely would replace it in a similar fashion and not question it much if at all.

Exactly!..........................