New consumer unit/electrician advice

[mtt.tr]

Due no doubt to the **** poor terminations in the MCB's and the use of plated steel screws instead of brass. Properly tightened brass screws do not come lose! We were trained to tighten till the brass squeaked, I have had MCB screws shear off before the same torque was achieved. How about another reg to put all the wago type connectors in fireproof enclosures? Another side to the problem is the amount of chinese counterfiet electrical gear that is about, and is being sold (unknowingly) through wholesaler networks! The problem was allowed for under the old IEE regulations which said " No circuit breaker or other mechanical device shall be fitted to any final sub circuit as a SOLE means of protection" In other words, all circuit breakers must be backed up with a fuse to prevent overcurrent. Fuses fail safe, MCB's and the like DO NOT!

Mcbs have multiple methods of tripping and dont rely on one method.

 

[hermetic]

Mcbs have multiple methods of tripping and dont rely on one method.

And yet enough of them have caught fire for the IET to introduce the metalclad and firesealed regulations? This is a sticking plaster on bad engineering, it would be better to eliminate the reason they catch fire..............by adding fuse protection as a back up! This is a classic example of "Never admit you got it wrong" The new regulations are a nightmare of gobbledygook. When you need a guide to understand regulations, whoever drafted them got it wrong too!

 

[mtt.tr]

And yet enough of them have caught fire for the IET to introduce the metalclad and firesealed regulations? This is a sticking plaster on bad engineering, it would be better to eliminate the reason they catch fire..............by adding fuse protection as a back up! This is a classic example of "Never admit you got it wrong" The new regulations are a nightmare of gobbledygook. When you need a guide to understand regulations, whoever drafted them got it wrong too!

Fuse protection won't protect against high resistance connections which is the cause of the fires, not mcb failures

Fires increased at the period of smart meters as in the act of moving the tails they loosen in the cage terminals on the cutout switch with is protected by a bs88 fuse and poorer quality terminals is the cause


Poor installation and low standards are the issue the regs have made things safer rather than reduce safety.

 

[hermetic]

Fuse protection always protects against a higher current flowing than the circuit is designed to carry. It is fail safe. MCB'S are not fail safe (read the guide to the regulations for confirmation of this) Poor workmanship, or poor design of terminals can and should be avoided by proper training, and proper design of equipment. It is obvious that if this has happened on multiple occasions (and it has) then something is Wrong with both and a metal enclosure and some intumescent sealer is most certainly not the right answer. Are you saying that the terminals can only maintain a safe connection if the cables are not moved? If that is the case, then they are obviously inadequate for the function they are supposed to perform. Are you trying to justify poor workmanship and bad design?

 

[WorkshopChris]

We are getting way fftopic: but.

but you will need a metalclad consumer unit, fireproofed so as to keep any fire inside itself. Although you will scarcely get anyone to admit it, this is because trips occasionally fail to trip in fault conditions, and then they catch fire, as the only downstream protection after the trip is the 100amp cut out fuse. Of course many thousands of plastic consumer units with trips have been fitted In the interim before the new metalclad rule, and these now pose a risk of fire which would not exist with an old wylex rewirable!

If the MCB was to fail the fire wouldn't start in the consumer unit with its great big copper bars, it would happen at the load/fault end of the cable.

Fuse protection always protects against a higher current flowing than the circuit is designed to carry. It is fail safe. MCB'S are not fail safe (read the guide to the regulations for confirmation of this)

All the burnt cables I have seen have been the result of high resistance at a joint/connection or through physical damage of the insulation either between phases, neutral or earth.

A modern MCB is incredibly safe and more likely to trip than to not operate.
One reason why they are not to be used for fire pump supplies where only fuses should be provided to guarantee the longest possible operation of the load.

 

[dobbslc]

"MCB'S are not fail safe (read the guide to the regulations for confirmation of this) "
If MCB's used on their own weren't compliant with the regs everything would have a similar sizes fuse as back up! That's not the case though.
The regs do state that RCD's shouldnt be used as the sole means of fault protection so need back up from an MCB or fuse. Admittedly Wylex had a bad batch of 6 A MCB's years ago that didn't trip on overload but I'd still much prefer an MCB to a rewirable fuse!
You're dead right about the bloody regs book though! Its almost impossible to work out some parts of it, the obsession with referring to this reg or that reg all spread out through the book seemingly in no sensible order is bad indeed.
Another thing about terminals in my experience is that almost none will hold a stranded cable tight if its moved around, doesn't matter how tight you do it up.
Why the electricity suppliers think it's ok to swap a meter over without re-tightening the main switch terminals is mental!
The oppsite way round is when I'm changing a D/B, I'll cut the seal off and tighten the head screws up, I can always get at least half a turn on them!
I don't give a toss about their outdated rules on what I can or can't do, if a house burns down two days after I've swapped a board over because the supply side of the meter tails were loose they won't give a monkeys as they'll blame me!

 

[brightspark]

I was at the wholesalers and they were trying to sell me a torque screwdriver over 100 quid I just said no thanks I don't need one after 47 years in the job I haven't had meter tails or any other tails burn out . I was working on a job with another electrician who had the torque screwdriver and watched him tighten the tails to correct torque and I asked if that was it . yes why . watch this gave the tails a bit of a rogering round and asked him to torque it again and he got half a turn on the loose cables moved it again and it was still tight as it had settled in .just good practice and a lot of experience. https://www2.theiet.org/forums/foru...d=50871&STARTPAGE=3&FTVAR_FORUMVIEWTMP=Linear

 

[mtt.tr]

I was at the wholesalers and they were trying to sell me a torque screwdriver over 100 quid I just said no thanks I don't need one after 47 years in the job I haven't had meter tails or any other tails burn out . I was working on a job with another electrician who had the torque screwdriver and watched him tighten the tails to correct torque and I asked if that was it . yes why . watch this gave the tails a bit of a rogering round and asked him to torque it again and he got half a turn on the loose cables moved it again and it was still tight as it had settled in .just good practice and a lot of experience. https://www2.theiet.org/forums/foru...d=50871&STARTPAGE=3&FTVAR_FORUMVIEWTMP=Linear

Ive got one and its sole function is to tick a box

 

[brightspark]

Ive got one and its sole function is to tick a box

when they brought them out they were supposed to be tested every year and a cert given . same as crimping tools guess what happened . NOTHING the nic eic sit there every year wondering what to change so they can justfy there jobs

 

[mtt.tr]

when they brought them out they were supposed to be tested every year and a cert given . same as crimping tools guess what happened . NOTHING

Its almost like money is more important to them, surely not?

 

[brightspark]

I do like most of the new regs mind mainly no more bonding everything in sight

 

[ajlelectronics]

Its almost like money is more important to them, surely not?

We had the same thing with the CAI. They turned from a useful organisation into a club for the boys, at the members' expense. The final straw for me came when they got into bed with the elfin safe tea bunnies and started issuing demands that we comply with the most ridiculous nonsense.

 

[mtt.tr]

I do like most of the new regs mind mainly no more bonding everything in sight

I like bondage personally

 

[gaz1]

I like bondage personally

you would be put on the joiners horse

 

[WorkshopChris]

I was at the wholesalers and they were trying to sell me a torque screwdriver over 100 quid I just said no thanks I don't need one after 47 years in the job I haven't had meter tails or any other tails burn out .

Ive got one and its sole function is to tick a box

One of the current bunch of YouTube electrical guys is an electrician/jobbing builder I have seen him set a torque screwdriver to the correct setting then, in turn, go through each pre tightened terminal one by one.
If you have it either use it to tighten the terminals or don't bother. Just the same as tyre fitter who uses an air gun then uses the torque wrench till it clicks. If the screw was already tight the click means nothing.

 

[mtt.tr]

One of the current bunch of YouTube electrical guys is an electrician/jobbing builder I have seen him set a torque screwdriver to the correct setting then, in turn, go through each pre tightened terminal one by one.
If you have it either use it to tighten the terminals or don't bother. Just the same as tyre fitter who uses an air gun then uses the torque wrench till it clicks. If the screw was already tight the click means nothing.

My tyre guys seem to think its click plus two extra pulls. Numpties some of the YouTube ones come across pretty clueless

 

[MetalMonkey]

Tighten it till you hear the snap, then back it off an 1/8 of a turn.
Or the other fitters favourite, three white knuckles and a swing on it for luck.

 

[dobbslc]

I thought it was half a turn???

 

[MetalMonkey]

I thought it was half a turn???

Depends on the calibration value...