Overtightening Meter Terminals

[littlespark]

I’d be doing my 5, then going round them again to double check they haven’t worked loose.

Agree with what’s been said above. Many terminals now come with a recommended torque value.
If we overtighten a mainswitch or something, you can be left with a shattered device.
I guess meter terminals are more sturdy.

The trouble here is a lot of your colleagues won’t have the thought of “am I doing this right?” Just hit the targets and get paid.
If you bring up the issue to management above you, you may not get any back up from fellow workers.

 

[Flipsy]

I’d be doing my 5, then going round them again to double check they haven’t worked loose.

Agree with what’s been said above. Many terminals now come with a recommended torque value.
If we overtighten a mainswitch or something, you can be left with a shattered device.
I guess meter terminals are more sturdy.

The trouble here is a lot of your colleagues won’t have the thought of “am I doing this right?” Just hit the targets and get paid.
If you bring up the issue to management above you, you may not get any back up from fellow workers.

This exactly, meter terminals are very sturdy a bit too sturdy as I think the cable will give out more then the terminal.
I understand all companies have targets but I think it’s irresponsible to promote people on speed of an installation rather then workmanship

 

[pirate]

Targets! Don't get me started!
The target system has caused more damage to this country than you will ever know...
Targets result in poor quality, anxiety for the workforce and more greed by the employers.
In my experience, if you tell your staff what would be a good turnover, but don't insist on it, they always perform better, go the extra mile, and don't try to hide shoddy performance because there rarely is shoddy work...they are relaxed, do a good job and customer feedback is positive.
Targets?
NO!!!!

 

[westward10]

I always wrap the conductors and they rarely need retightening as conductors don't shift.

 

[Pete999]

I always wrap the conductors and they rarely need retightening as conductors don't shift.View attachment 49740

very old school Mate, as did I

 

[Andy78]

I always wrap the conductors and they rarely need retightening as conductors don't shift.View attachment 49740

That's not gonna fit in with the targets man, keep up !

 

[Pete999]

That's not gonna fit in with the targets man, keep up !

WGAM's Mate it's correct procedure

 

[Simon47]

I always wrap the conductors and they rarely need retightening as conductors don't shift.

Would the modern equivalent be using bootlace ferrules ?

I've been on the other side of the "is it tight" problem. Was doing some work in a church and the meter fitter has obviously had the strength of a weak spider - almost every terminal was loose. I had someone in from the DNO for other reasons, and while he was sorting out the neutral block (removing a redundant neutral cable, and fixing the "strand missed the hole" problem with the neutral tail from the meter) he ... found the other end of the neutral tail seemed loose.
Opened up the meter to check (if he hadn't noticed it, I was going to ask) and all six tails were loose - and the neutral had come out
As best I can tell from the meter change ticket, it was done about 9 years ago by BG (or someone working for them).

 

[Wilko]

Hi - apologies if I’m repeating earlier posts (lazy Saturday afternoon) but each manufacturer will have a torque setting. As an example, this one is 2.8 Nm, on page 20 of the instructions in the link.

https://www.rayleigh.com/media/uploads/A100C_Operating_Instructions.pdf

 

[stevels4]

Would the modern equivalent be using bootlace ferrules ?

I've been on the other side of the "is it tight" problem. Was doing some work in a church and the meter fitter has obviously had the strength of a weak spider - almost every terminal was loose. I had someone in from the DNO for other reasons, and while he was sorting out the neutral block (removing a redundant neutral cable, and fixing the "strand missed the hole" problem with the neutral tail from the meter) he ... found the other end of the neutral tail seemed loose.
Opened up the meter to check (if he hadn't noticed it, I was going to ask) and all six tails were loose - and the neutral had come out
As best I can tell from the meter change ticket, it was done about 9 years ago by BG (or someone working for them).

“all six tails were loose” what type of meter was that as they are generally 4 or 5 on SP or 8 on 3P

 

[DefyG]

Recently did a consumer unit that specified 2.4Nm for the main switch terminals which were 25sq.
Think it would be worth investing in a torque set 'for your own benefit' if unsure how tight the meter terminals should be, but as a guide 2.4Nm!

 

[DefyG]

Wouldn’t know , I use my impact driver these days ...

Have you never had to replace a breaker or carry out an EICR where 'someone' (Language is stronger on-site!) has used an impact drill to tighten the terminals and you cant get undone?

 

[Pete999]

Have you never had to replace a breaker or carry out an EICR where 'someone' (Language is stronger on-site!) has used an impact drill to tighten the terminals and you cant get undone?

An impact driver to tighten cable terminations is nothing short of Butchery, using this type of driver for terminating is all down to get it done, get paid and FTO.

 

[Charlie_]

I used to enjoy splitting the earth wire round a bolt and then wrapping the spare conductor round the base

 

[Zerax]

Sometimes if you tighten it and then give it good wiggle you'll find it can be tightened a bit further because the strands have moved

But one man's "good wiggle" is not always the same as another man's "good wiggle"...

 

[Simon47]

“all six tails were loose” what type of meter was that as they are generally 4 or 5 on SP or 8 on 3P

It is a 3ph meter on a 1ph supply. I have no idea why he didn't use a Henley block on the live side - but he used two phases on the meter and fitted two isolators to feed the 4 fuseboards

 

[Pete999]

Wouldn’t know , I use my impact driver these days ...

Then you ought to be ashamed of yourself DD

 

[Zerax]

7 strand. We aren’t aloud allowed to put 19 strand into a meter. Have to be blocked or replaced if we find those.

Corrected that for you.

 

[Pete999]

I used to enjoy splitting the earth wire round a bolt and then wrapping the spare conductor round the base

Spare conductor?????????????

 

[Dustydazzler]

I don’t actually use an impact driver for terminations

I just use a regular screw driver

But I have witnessed some of the ‘young breed’ use impacts on consumer units

 

[Simon47]

It is a 3ph meter on a 1ph supply. I have no idea why he didn't use a Henley block on the live side - but he used two phases on the meter and fitted two isolators to feed the 4 fuseboards

Photos of the "workmanship" of the sort that such targets, plus the use of "not exceedingly well trained" meter fitters produces The OP clearly sets himself higher standards judging by the way he's asking the questions

Yes, these tails are fully inserted. The neutral here actually came out of the terminal when I moved the tail while working out what went where


And the complete work of art. Bonus points if you can spot what's going on with the neutrals !



BTW, if anyone wants any of the old fuseboards for their museum, they are yours for the postage.

 

[Dustydazzler]

that’s a beauty

 

[Simon47]

We aren’t aloud to put 19 strand into a meter. Have to be blocked or replaced if we find those.

Well that sounds like a rule dreamed up by a complete idiot. The mind boggles at why you would be forced to replace a good cable with a very inferior one. Whoever dreamed that rule up would have kittens if they saw what I used on the church job - lovely easy to work with 6381Y

 

[Pete999]

Hello guys and girls I was wondering if you have any advice to give to a meter installer. I’m often worried about over-tightening terminals inside the meter. How easy is it to break the strands on 16mm copper or 25mm? I tighten the terminal until I can’t tighten them anymore. But I’d this right or should I be just tightening until I feel enough resistance? We never used to have this problem with the old meters as they were flat head terminals and you couldn’t get a lot of torque on them. But these Modular screws with plus and minus screw drivers get a lot of torque on them and I’m worried I could damage the strands.

The problem is Flipsy, all pride has disappeared from many parts of this electrical trade, all emphasis is on targets not workmanship, from reading through this thread, there have been some shocking revelations, people using impact drivers to tighten connections, one very good idea was posted by Westward 10, binding the bare conductor with a strand of scrap wire, I will ad that during my apprenticeship I was always taught to do this, as well as tinning the connection as an extra precaution ( using a Mentholated Spirit blow lamp) whatever happened to those? most of the Electricians I worked under had these items in their tool kits.

Mind you in those days Electricians were trained properly, and of course, this method doesn't fit in with todays bish bash bosh culture more's the pity.

Sorry for the rant, ask your employer for a torque screwdriver set to enable you to maintain the correct setting for the connections, the trouble is they may stick you down as a trouble maker, a no win situation really.

What ever good luck and don't let the boogers grind you down.

 

[Great68]

Before we had torque drivers I had snapped a few meter screw heads but never cut into the cable

 

[Simon47]

...
Sorry for the rant

That's not a rant, it's a statement of facts - sad though it is to see them laid out like that and how bad things have become

ask your employer for a torque screwdriver set to enable you to maintain the correct setting for the connections, the trouble is they may stick you down as a trouble maker, a no win situation really.

I would add, ask in writing if that's practical - Flipsy, do you have a work email address ? Just ask by email, and print it after you've sent it; when you get a reply, print that; keep both at home.
One Pete left out was the CYA factor. The reason for saying to print the emails and keep the printouts at home is if something goes wrong and the finger gets pointed at you. An unscrupulous employer/manager will be more than happy to make the person doing the work into a scapegoat. You want to be able to show that you did all you could - and if, for example, they won't give you the right tools be able to show that you asked and they refused.
In other words, always make sure you CYA

 

[Bobster]

Spare conductor?????????????

I know what he means, I was taught the same at the beginning of my career. Now that crimps and ferrules are so abundant, it's not done anymore.

7 strand conductor, 3 are taken round each side of the bolt. Then the 7th wraps around the returning 6 strands and locks them in place.

 

[Pete999]

I know what he means, I was taught the same at the beginning of my career. Now that crimps and ferrules are so abundant, it's not done anymore.

7 strand conductor, 3 are taken round each side of the bolt. Then the 7th wraps around the returning 6 strands and locks them in place.

Ah thought that may have been the case, just wanted reassurance.

 

[Carl S]

I know what he means, I was taught the same at the beginning of my career. Now that crimps and ferrules are so abundant, it's not done anymore.

7 strand conductor, 3 are taken round each side of the bolt. Then the 7th wraps around the returning 6 strands and locks them in place.

I’ll bet like me you were shown married, britannia, spliced tee and scarf joints. I used a married joint once on an overhead line, 7/064 HD to 19/044. Line taps would have been easier.

 

[Bobster]

I’ll bet like me you were shown married, britannia, spliced tee and scarf joints. I used a married joint once on an overhead line, 7/064 HD to 19/044. Line taps would have been easier.

Yes, I was taught this also, and pretty proficient at them too.

However modern connectors make life a damn site easier an quicker. Although falling back on these skills has pulled me out of the mire a few times.

 

[Pete999]

Yes, I was taught this also, and pretty proficient at them too.

However modern connectors make life a damn site easier an quicker. Although falling back on these skills has pulled me out of the mire a few times.

 

[Pete999]

Yes, I was taught this also, and pretty proficient at them too.

However modern connectors make life a damn site easier an quicker. Although falling back on these skills has pulled me out of the mire a few times.

Imagine the training Places teaching that, have to train the trainers first

 

[Bobster]

Imagine the training Places teaching that, have to train the trainers first

There are still some good training centers and trainers around Pete.

In fact even mine, I learned more in the first month on site than I did in my first 12 months at the centre. (We all had to do 12 months before we were allowed on site.)

 

[Pete999]

There are still some good training centers and trainers around Pete.

In fact even mine, I learned more in the first month on site than I did in my first 12 months at the centre. (We all had to do 12 months before we were allowed on site.)

Agree Rob I do tend to generalise on occasions

 

[Carl S]

Imagine the training Places teaching that, have to train the trainers first

I qualified as a trainer of trainers (AKA teach people how to teach), I hated the course. It was part of a man people management NVQ.

 

[westward10]

So here is a connection I made to a bonding clamp today. I have wrapped it and the clamp can be tightened no more, even went back to it and is still rock solid. You will notice the conductor has retained its shape with no shift to the strands.

 

[Flipsy]

Had a scare today tightening, screw all the way right with a modular driver then went over them again then last time with a flat head. Heard creek/crack on one of the screws. Undid it, looked in the barrel, looked at the screw, replaced the screw. Tightened all up again and bit the wire no visible cracks and still tightened. So I dunno what went wrong there. Checked everything made sure nothing was cracked or broken and the new screw didn’t just turn in the barrel either.
This just wouldn’t happen with a torque driver. I tugged the wire as well. I also for peace of mind have taken apart a spare electric meter and basically tried destroying the cables, the terminals with a drill to tighen and done everything in my power to cause as much damage as I can above what I would normally do and everything seems fine on the test meter. So I think I’m clearly worrying over nothing. But I like to test things to destruction to see how fragile the equipment I’m working with is.
I think the weird crack noise might have been either the screw turning a bit and making a squeak or the flat head slipping slightly. But could not find anything damaged.

 

[Simon47]

It's not uncommon to get some sort of "crack" when nipping up an already tight terminal (or nut and bolt, or ...). Once tightened and static, there is significant stiction to be overcome before it will move again - so you apply pressure, nothing happens till you overcome the stiction, then there's a release as things move before settling down at the dynamic friction level which is much lower for most materials.
Few materials, brake pad linings are one of them, have stiction that is lower than dynamic friction - hence the effect of "nothing happens, then something 'gives', and things move with less effort than needed to get it moving". This is also why it's generally a good idea to loosen something before checking it is tight to a specific tightness level - if it's already tight, it may be stuck in place (especially with something like a steel wheelnut against a steel wheel and which has been in place for a long time) and the torque wrench setting isn't sufficient to overcome the stiction and you get a false sense of tightness.

 

[Flipsy]

It's not uncommon to get some sort of "crack" when nipping up an already tight terminal (or nut and bolt, or ...). Once tightened and static, there is significant stiction to be overcome before it will move again - so you apply pressure, nothing happens till you overcome the stiction, then there's a release as things move before settling down at the dynamic friction level which is much lower for most materials.
Few materials, brake pad linings are one of them, have stiction that is lower than dynamic friction - hence the effect of "nothing happens, then something 'gives', and things move with less effort than needed to get it moving". This is also why it's generally a good idea to loosen something before checking it is tight to a specific tightness level - if it's already tight, it may be stuck in place (especially with something like a steel wheelnut against a steel wheel and which has been in place for a long time) and the torque wrench setting isn't sufficient to overcome the stiction and you get a false sense of tightness.

Thanks really good advice. Makes me sleep easier at night lol.