Consumer Unit Bus-bar M.C.B. reliable clamping.

This is what the I.E.T. should do something about……

But they did didn't they? 421.1.201 (OK perhaps not the ideal thing, but it was something)

   - Andy.

If you look carefully Z you will see that the busbar connections are a little curious. I don't know why but ….

The fire in that CU was above the MCBs, why was that? It could have been the main switch which is completely missing, but still not as simple as it looks.

AJJewsbury: 
 

This is what the I.E.T. should do something about……

But they did didn't they? 421.1.201 (OK perhaps not the ideal thing, but it was something)

   - Andy.

The poster of the video was referring to M.C.B. design where it is possible to get the bus-bar finger the wrong side of its cage clamp, where it just makes fortuitous contact, and is not gripped securely.

Z.

davezawadi (David Stone): 
 

If you look carefully Z you will see that the busbar connections are a little curious. I don't know why but ….

The fire in that CU was above the MCBs, why was that? It could have been the main switch which is completely missing, but still not as simple as it looks.

Indeed Dave, the prime suspect seems to be the main D.P. switch. Also the M.C.B.s did not burn, it was mainly the P.V.C. insulated cables. 

I once came across a 40 Amp M.C.B. that had not gripped its bus bar finger securely as the cage was positioned incorrectly. There was no sign of heat damage. I assumed that the short usage of the shower did not allow sufficient time for a dangerous build up of heat.

I have just been working on an old Crabtree C50 dis. board. What a great reliable design with proper visible screws to secure the M.C.B.s to the bus-bars. A wonderful reliably clunky old British design and manufacture.

CRABTREE 5 AMP SINGLE POLE/PHASE MCB CIRCUIT BREAKER 5A C-50 OLDER STYLE BS3871 | eBay

Z.

The poster of the video was referring to M.C.B. design where it is possible to get the bus-bar finger the wrong side of its cage clamp, where it just makes fortuitous contact, and is not gripped securely.

But obviously not the cause in this case … as the one that burned didn't have a finger-type bus-bar.

   - Andy.

A concern for the connection of EVSE to existing boards, which, in my opinion, far exceeds the PME risk!

All-brass twin screwed tunnel terminals would be the way to go. If Proteus can do it with their equivalent of the Wylex AC2 isolators for the DNOs then surely it could be done for consumer unit terminals too.

I agree with the comments with regard to the tighten-it-up skills being taught, but you are still left with a turd which stubbornly remains unpolishable when it comes to dodgy cage clamps being permitted for heavy current terminations.

AJJewsbury: 
 

The poster of the video was referring to M.C.B. design where it is possible to get the bus-bar finger the wrong side of its cage clamp, where it just makes fortuitous contact, and is not gripped securely.

But obviously not the cause in this case … as the one that burned didn't have a finger-type bus-bar.

   - Andy.

Yes Andy, we all know that.

Z.

I think fortunate that it was in the garage and not indoors.

I still think that my design for the tails to the main switch connection needs some more interest, I'll try to post the pictures again later. Keeping tails firmly clamped is a problem that keeps coming up.