Limiters

[mstrlucky74]

So if I have 3 hots in one set and I had 5 sets would I onlyneed one limiter for all of the A phase conductors or would I need 5 separate limitersfor each A phase conductor? Either situation obviously applies to the otherphases as well. Thanks.

 

[infinity]

You need one limiter per phase conductor. Neutral conductors do not get limiters.

 

[mstrlucky74]

You need one limiter per phase conductor. Neutral conductors do not get limiters.

View attachment 19203

Thanks

 

[domnic]

limiter

limiter

What article 2011 nec ?

 

[infinity]

230.82 and 450.6.

 

[mbrooke]

Call my dumb- but what are limiters? And why use them?


Only seen limiters (not sure if these are the same) in POCO Networks- the idea is that they "fuse" open before the conductor melts since such systems requires one to burn clear for a fault.

 

[infinity]

Basically an fault in one of the parallel conductors will cause the limiter to open and not take down the entire feeder or system. The ones in the photo I posted are on the utility side of the service disconnect.

 

[mbrooke]

Basically an fault in one of the parallel conductors will cause the limiter to open and not take down the entire feeder or system. The ones in the photo I posted are on the utility side of the service disconnect.

Ahhh- ok.

But what stops the other conductors from over heating? Id imagine an open limited does not make itself known?

 

[ron]

Since it says to provide the limiters per the NEC ...... and the NEC does not require them, it does however permit them, do you not have to install them?

Agreed, one per individual phase conductor.

 

[ron]

Ahhh- ok.

But what stops the other conductors from over heating? Id imagine an open limited does not make itself known?

It does not make itself known when it fails, that's why I hate them.

One time I tried to monitor them, by monitoring voltage on either side, like a fuse monitor system, but it was not allowed by the jurisdiction.

 

[steve66]

Ahhh- ok.

But what stops the other conductors from over heating? Id imagine an open limited does not make itself known?

The other limiters. If you have a heavily loaded feeder running at near capacity, once one limiter opens, the others will quickly follow along.

But if a feeder has a lot of spare capacity, you might never know that a limiter is open.

 

[steve66]

Basically an fault in one of the parallel conductors will cause the limiter to open and not take down the entire feeder or system. The ones in the photo I posted are on the utility side of the service disconnect.

I thought they just protected each individual wire against overcurrent.

I guess they would also protect against a ground fault, but they would have to be installed on both ends of the feeder, right?