Current transformer circuit "stab" test

[@aljohnson3717]

Guys, please! Do NOT plug your Flukes into the CT secondary! Even though Fluke has 10Amp fuse at its "Amp" terminal, you might find yourself in trouble if you are close to that fluke, measuring secondary current during some heavy fault. Your fuse will blow and have CT secondary open. The voltage at secondary will build up to tremendous values and could potentially kill you. Don't plug your Fluke into loaded CT!

[@TradieTrev]

That's pretty handy, haven't seen those blocks before. Normally we'd be reduced to having to remove the motor panel or a isolator so we could squeeze a clamp meter on.

[@paulrackouski6609]

It’s not a smart idea to use a fluke when doing this.. since the fluke is fused, you have a risk of opening the CT string.

[@Boldaslove71]

I second that. If a fault occurs (over 10A), the CT is open and BOOM. There are clamp on A/mV transducers that can be used.

[@dibraniuk]

There is no danger as long as the probes stay firmly plugged in and the fuse will not blow - there is noway since a short is good! for CT /in this case. Fuse will only blow if short circuiting a voltage source. This is a current measurement!

[@Chris-cv7qy]

DO NOT use that "probe" you call it for jacking into ct secondary's. Right in the middle is an insulating piece of material and if you insert it incorrectly by mistake you will be creating an open circuit condition with your test equipment!!

[@dibraniuk]

There is no danger as long as the probes stay firmly plugged in and the fuse will not blow - there is noway since a short is good! for CT /in this case. Fuse will only blow if short circuiting a voltage source. This is a current measurement.

[@neilshepard2666]

Where do you find such a probe?