Current Transformer

[Neal Lewis]

I've run across several current transformers over the years, always in big houses of course.

Does anyone open the covers of these beasts?

And is the purpose of the CT strictly for metering?

The one I saw the other day did not have an amperage rating, but was rated for 600V, and had a rating for max 750 kcmil? parallel cables. I've never seen that rating before.

Thanks

[Chad Fabry]

750kcmil is a big wire. K=one thousand and "circular mils" are .001" graduations in diameter. So 750 is 3/4 of an inch in diameter..conductor size.

[chicago]

Not something I would mess with.

[Jim Katen]

Originally posted by Neal Lewis

I've run across several current transformers over the years, always in big houses of course.

Does anyone open the covers of these beasts?

Current transformers will either be up at the weatherhead or down in a box. If they're in a box, there's almost always a power company seal on the box. Don't break the seal. There's really no reason for a home inspector to be mucking around in there anyway.

And is the purpose of the CT strictly for metering?

Pretty much. In my area, they hardly ever use them on residential services anymore. All of the newer 400-amp services use class 320 meters that don't require CTs.

The one I saw the other day did not have an amperage rating, but was rated for 600V, and had a rating for max 750 kcmil? parallel cables. I've never seen that rating before.

Thanks

Yeah, but that was the max. I'm assuming that the cables you saw were much smaller.

- Jim Katen, Oregon

[zekideguito]

most of the current transformer are we used 600:5, 800:5, 1200:5 for three phase transformer.

then you can use smaller one wire.

http://electricalengineeringtour.blogspot.com/