What are these devises?

[Trent Tarter]

Not sure what theses devises are, possible surge protection?. They're attached to both service masts, home has 2-200 amp panels. They are connected to smaller service mast in center, wish I would have taken some better pictures, any ideas what these are for. Wire insulation looks a little rough.

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[Erby]

Look to be current transformers but it's been awhile since I've had anything to do with those.

And then it was for metering equipment for three-phase large amp electrical supplies in large shopping malls.

[John Kogel]

I think the correct term would be current 'meters', because they measure the current flowing through those conductors.

[Erby]

Actually John, it's "transformers":

"When current in a circuit is too high to apply directly to measuring instruments, a current transformer produces a reduced current accurately proportional to the current in the circuit, which can be conveniently connected to measuring and recording instruments. A current transformer isolates the measuring instruments from what may be very high voltage in the monitored circuit."

Though a bit unusual to find in a residential application.

[Marc]

Erby got it. Don't recall ever seeing one outdoors though.

I had a friend years ago who dealt in used industrial power equipment. He had a need to test high amperage devices and was short on funds so I picked out an industrial voltage transformer from his stock, altered the turns ratio, added a small 120 volt variable transformer to the primary and made him a current source that could deliver several hundred amps. It could smoke a 2/0 in seconds.

Marc

[John Kogel]

Thanks, Erby. For the transformation.

Marc, I imagine there were some funky smells wafting around your buddy's shop from that smoking insulation. []

[Neal Lewis]

This is the typical current transformer I see at mega-houses. Usually in the basement though.

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