Got away with that one....

[Rockingit]

Because none of us are beyond schoolboy errors..........

Doing some events kit testing over the weekend, some larger metal stand distro panels that we'd had to custom make for a job (800A in, 125/3 and 63/s out's [commando sockets]) and came to testing the adjustable RCD's, so time to energise them from an adjacent generator with RCD disabled.

I've a whole variety of test leads made up for this - mostly 4mm banana leads coming out from a relevant sized plug so that you can just plug direct into your meter - some of which are the stackable type so if you're doing cable dead tests for continuity you can just short out one end for r1r2 tests by plugging the two ends together. You can also stack all five together for really quick IR tests.......

The panel's live, I'm tired and not paying full attention, I plug in a test plug with one hand whilst reaching for my meter with the other, colleague switches the MCCB on from the other side...... "why's the generator just stopped?" Me, looks down... "Err..... might have something to do with the dead short L1+L2+L3+N on this set of test leads!!" Mind you, these 4mm test leads, that were cradled in my hand at the time, hadn't even so much as twitched as it happened - one can only guess at the pfc in that combination!! (If anyone actually wants to work it out, the Z would likely have been around 0.2). Kinda glad about that - I quite like my fingers!!!

The electronic sense protection built in to the generator control panel had knocked the shunt trip out a long time before anything else downstream got warm - it's good to know that technology works.

 

[timhoward]

I did a similar thing - on Metrel test leads you test IR with the blue and brown leads and the the plugs on the end are stackable. Adding another normal 4mm lead makes L+N to E testing simple as you get a probe/clip for everything. I put the right colour clips on everything and test the L-E clips and N-E clips checking I get zero. Then crack on.
This works fine until you get a phone call, then get offered cake and tea and chat politely with customer for 5 minutes, and then another phone call and you forgot you were doing IR before all these distractions. I just swapped the clips for probes, like for like, without engaging brain.
Pushing brown and blue probes into the load side of an RCD definitely DID twitch the probes with impressive sparks as there was still a test lead directly connected between them! Customer was still there and had just said "I don't know how you understand all those wires.". I was just saying "you get used to it" when the sparks started!

 

[mainline]

I did a similar thing - on Metrel test leads you test IR with the blue and brown leads and the the plugs on the end are stackable. Adding another normal 4mm lead makes L+N to E testing simple as you get a probe/clip for everything. I put the right colour clips on everything and test the L-E clips and N-E clips checking I get zero. Then crack on.
This works fine until you get a phone call, then get offered cake and tea and chat politely with customer for 5 minutes, and then another phone call and you forgot you were doing IR before all these distractions. I just swapped the clips for probes, like for like, without engaging brain.
Pushing brown and blue probes into the load side of an RCD definitely DID twitch the probes with impressive sparks as there was still a test lead directly connected between them! Customer was still there and had just said "I don't know how you understand all those wires.". I was just saying "you get used to it" when the sparks started!

You should have said, “And that's the spark gap test done”

 

[Rockingit]

I did a similar thing - on Metrel test leads you test IR with the blue and brown leads and the the plugs on the end are stackable. Adding another normal 4mm lead makes L+N to E testing simple as you get a probe/clip for everything. I put the right colour clips on everything and test the L-E clips and N-E clips checking I get zero. Then crack on.
This works fine until you get a phone call, then get offered cake and tea and chat politely with customer for 5 minutes, and then another phone call and you forgot you were doing IR before all these distractions. I just swapped the clips for probes, like for like, without engaging brain.
Pushing brown and blue probes into the load side of an RCD definitely DID twitch the probes with impressive sparks as there was still a test lead directly connected between them! Customer was still there and had just said "I don't know how you understand all those wires.". I was just saying "you get used to it" when the sparks started!

I've a Metrel as well as a Fluke and totally understand that!! The thing I dislike about them too is that because you're forced to use their own leads due to the big black plug I always find I end up in a massive tangle of overly long leads. However it wins over the Fluke on RCD testing functions >500mA

 

[pc1966]

Good to know nothing went terribly wrong.

Also good to know as soon I have to fiddle with the supply on our site while keeping most of it going and my cunning plan was to force over to the backup generator just in case I make a mistake as it should result in far less flying molten metal!

 

[Rockingit]

Good to know nothing went terribly wrong.

Also good to know as soon I have to fiddle with the supply on our site while keeping most of it going and my cunning plan was to force over to the backup generator just in case I make a mistake as it should result in far less flying molten metal!

You sure about that?! In fairness, this was downstream of 2.5MVA generation, but…. (Also - absolutely NOT my incorrect work that blew itself apart!!! Someone got a very big -------ing for this.)

 

[Lister1987]

I've a whole variety of test leads made up for this - mostly 4mm banana leads coming out from a relevant sized plug so that you can just plug direct into your meter

Same, only have them for 16 & 32 3P+N / 3P+N+E, which do you tend to find at 125A? Imagine you've got some Power Con/ConLok/SOCOPAX fraken-leads too?

 

[Rockingit]

Same, only have them for 16 & 32 3P+N / 3P+N+E, which do you tend to find at 125A? Imagine you've got some Power Con/ConLok/SOCOPAX fraken-leads too?

Pretty much everything up to 125 3PNE (U.K.) Also have leads and adapters for a variety of overseas stuff too, mostly American. Not interested in Socapex as generally speaking it just serves as a transport for 6 x 16A / 15A each end so you test using what’s appropriate for that. Anything above 125A will tend to be Powerlock (up to 800A) so the safest route is Powerlock to 125A adaptor and then test from there - clearly under no load and strictly test conditions.