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Jeffrey L. Mathis
04-15-2009, 04:41 PM
I have an older home (inspection) with a Turnbull brand fused disconnect with 2 125 amp fuses. Do I call that a 250 amp disconnect? I think 125.
Thanks

JLMathis

Jerry Peck
04-15-2009, 06:27 PM
125 amp.

125 amps goes in one phase conductor, through the panel, and out the other pass conductor - each phase conductor has a 125 amp fuse, so either one will blow at 125 amps and you lose power.

Bill Kriegh
04-16-2009, 08:37 AM
On older wiring installations it is never a good idea to guess how things are hooked up. Normally the installation would indicate a 125 AMP service.

However, I've seen more than a few of these old services where both fuses feed from the same hot leg because the service originally had (and may still have) only one hot feed from the utility.

I've also seen these old services where the second fuse was actually installed in the grounded conductor, or neutral.

You could have a standard 125 AMP 240 volt service, a 250 AMP 120 volt service, or an illegally fused 125 AMP 120 volt service.

Keep in mind these 125 AMP fuses may be on a meter rated at 60 Amps. This is a common situation.

The voltage between the two fuses is necessary to answer part of the question unless 240 volt appliances are being used without problems.

John Steinke
04-17-2009, 06:29 AM
What does the lable say? The rating of the disconnect is completely separate from whatever fuses may be in it. In most cases, the disconnect is rated for the largest CORRECT fuses that can be used in it.

Jerry Peck
04-17-2009, 09:35 AM
What does the lable say? The rating of the disconnect is completely separate from whatever fuses may be in it. In most cases, the disconnect is rated for the largest CORRECT fuses that can be used in it.


John,

Sort of correct.

If you have a 250 amp rated disconnect with 125 amp fuses in it, you have a 125 amp disconnect (which was the term the original poster used).

In your defense, though, you would have a 250 amp RATED disconnect, but that was not the question.