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Insulation Resistance Tester with Remote Dead Man Switch

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OhioAviator

Electrical
Sep 8, 2003
123
Do any of you know of an insulation resistance tester (0 - 2500 V) that incorporates a remote dead man switch feature? We are getting ready to do a lot of insulation resistance testing on new construction in an industrial plant. I've been doing megger testing the old school way for years, but would feel a whole lot better if the person at the remote end of the cable had a 'dead man switch' he could attach between a phase conductor (not under test) and ground. He could then depress and hold that switch, which would then allow the megger at the other end of the cable to apply test voltage to the cable. If the person holding the dead man switch were to let go, the megger would automatically remove the test voltage.

If you've heard of such an animal, can you point me to a make and model?

Thanks!

J.R.

Galatians 2:20
 
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When doing a megger test, aren't the phases not under test already grounded in order to perform the test?

I'm not familiar with an application you are searching for. We've always done it safely via operation/testing procedures.

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This is normally the space where people post something insightful.
 
I've seen these switches only on Doble Insulation Testers, that can push up to 10 kV ac. Even hipots don't have this security feature and these can generate more than 100 kV dc.
 
Vitrek testers have the ability to connect remote control signals (start/stop/interlock). Not a ready made solution but by adding some additional components you could make it do what you want.
 
In the early days of lockout legislation, people were still being injured and killed despite the circuit being locked out according to regulations.
As a result, the early regulations were changed and locking out by locking out a control circuit was not recognized.
If you do not learn from history you may be doomed to repeat it.
Most implementations of a "dead-mans-switch" would depend on trusting a control circuit. A failure in the control circuit may leave the cable energized when the operator believes it to be safe.
The first danger of contact with a megger output is the physical reaction. Falling off of a ladder or other inadvertent movement.
The second danger is that a very long cable may store a large enough capacitive charge to be lethal.

Bill
--------------------
"Why not the best?"
Jimmy Carter
 
I was thinking the person at the far end would be "guarding" the exposed conductor under test. So, the switch would give this person the ability to abort the test if there was a reason to do so.
 
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