Keeping RCBOs Neat In A CU
Posted 13 March 2016 - 09:20 PM
Posted 13 March 2016 - 09:43 PM
Due to my marine panel wiring experience, I routinely left way too much ' re-termination ' slack in my CU's, to a point once when my good sparky mate refused to give me a sign off. He told me to cut back and re-make the cables to the breakers as there was too much of it .
Panel wiring, particularly on large ships, taught me to go around the perimeter of the CU at least once before cutting the tails to their respective terminations. Domestic wiring, it seems, doesn't favour my old habits .
IMHO, excess slack = problematic CU. Not saying cut it short, but they can be cut nevertheless.
Posted 13 March 2016 - 10:52 PM
Posted 14 March 2016 - 07:45 AM
I wonder why that very neat double busbar system isn't more common? It looks like it'll fit any standard width MCB or RCBO, as long as you don't get RCBOs with the pre-attached neutral. My pet gripe with those is that they use very thick (around 10mm²) cable for the neutral lead, even on the smaller 6 A RCBOs, which makes for a lot of clutter in there, even though they use very flexible silicone insulated wire.
Posted 14 March 2016 - 08:08 AM
"grown up" rcd's or rcbo's manage without an earth wire. I presume it's foir the test button to create a leakage to earth, but other types or rcd and rcbo simply put a resistance from one side of the sensing coil to the other to create an imballance without the need for an earth connection.
That compact board I only know of from one supplier. He imports the components and makes the CU's to your specific requirements. but as I say he's strictly trade only.
P.S I cut the fly leads to length to tidy tjhings up a bit.
Edited by ProDave, 14 March 2016 - 08:09 AM.
Posted 14 March 2016 - 08:27 AM
Posted 14 March 2016 - 08:33 AM
Posted 14 March 2016 - 09:53 AM
I see comment that cutting the leads off shorter is ok but they then need a new ferrule crimping on because the wire is too finely stranded to resist being destroyed by the neutral bar screw. That could be the leading cause of CU fires that led the inappropriate driving force of LFB to pressure for the inappropriate hash that is amendment 3!
Posted 14 March 2016 - 03:00 PM
Posted 14 March 2016 - 07:44 PM
Posted 14 March 2016 - 09:14 PM
I tend to twist 3 or 4 of those small wires into one and then double the end over before screwing the earth terminal tight.
Posted 14 March 2016 - 09:55 PM
Re the fine earth wires, I twsit a load together and put them into one terminal with a boot lace ferule. There are simply not enough earth terminals to put each of those silly little wires into one terminal and well as an earth terminal for each circuit.