Over-current protection before meter.

[truck41trouble]

Hello all,
I am a new member to this forum , but have used it almost exclusively to find answers to questions. I work for a utility company in the hudson valley region of Ny, and I also do industrial and commercial on the side as well as automation.

I have somewhat of a theory question, which may or may not have been discussed before. Why is there no code requirement for an ocpd to be installed after the utility transformer. I understand that utilities are not governed by the nec, but since a majority of meters are mounted on the structure it seems like it should be a thing. If a wire comes out of its lug or a lug breaks off and grounds against the side of the enclosure you can have a very violent situation. I know first hand that a fault like that will not trip a primary fuse, recloser, sectionalizer. And with most homes in this area being fed from an individual pot with no fuse protection, it makes sense to me. Im not talking about a cutout fuse on every service drop, but maybe a fusible link or somthing of that nature.

Like I said this may have been discussed multiple times before, but I haven't searched through, and figured this was a good way to introduce myself.
Connor



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[iwire]

You answered this yourself, the NEC can not require things that are on the utility side of the service point.

The NEC does requires overcurrent protection either outside or nearest the point of entrance of the service conductors.

The NEC has no say in where the meter is located in relationship to the over current protection.

That is up to each utility, some areas the power company will not allow a disconnecting means ahead of the meter, some power companies requires it. Some require disconnecting means ahead of meters more than 250 volts to ground but prohibit it under 250 to ground.


Beyond all that, while we can imagine all sorts of problems this lack of overcurrent protection will cause the reality is millions of successful installations without problems don show a need for a change.

 

[JFletcher]

Welcome. Like iwire mentioned, it doesnt happen often enough to be a concern. The few times it is here would be hurricanes, and power is out long before trees fall onto secondary lines and rip them from the service mast, or in the case here with Isabel in 2003, snapped the standoff and 60' of SE cable off the house and right out of the meter lugs.

 

[electricalist]

Only a guess but I'd say because anything ahead of the meter would have to be owned and possibly maintained by the poco.

A fault that would occur is better at clearing itself.

The poco would rather the fire department address the issue first.


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[ptonsparky]

Only a guess but I'd say because anything ahead of the meter would have to be owned and possibly maintained by the poco.

A fault that would occur is better at clearing itself.

The poco would rather the fire department address the issue first.


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Our Rural Power Districts did put 70 amp overcurrent devices below the pole mounted meters back in the 40s & 50s with some larger ones on up into the 70s, IIRC. That policy stopped when those units started needing to be replaced or upgraded. Our POCOs are not privately owned, for profit, utilities.

North of me, the POCO will provide non fused transfer switches with an additional cost to the owner for residential and farm buildings. Wells used to require fused disconnects at the poles, for some areas, but now the POCO install a Meter with a Size 4 starter in the enclosure.

AFAIK, with the exception of one OS moment, the transformers have always had primary fusing.