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.
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.