Overtightening Meter Terminals

[Flipsy]

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.

 

[Charlie_]

Do they not come with torque settings in the manufacturers instructions?

 

[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.

Did your employer issue you with instructions an suitable tooling?

 

[Flipsy]

Do they not come with torque settings in the manufacturers instructions?

No we do not get given torque screwdrivers for wiring meters. It’s done on feel alone. Hence why I tighten until I can’t tighten anymore. Just worried that could be damaging the copper strands.

 

[Flipsy]

Did your employer issue you with instructions an suitable tooling?

Suitable tools yes but no info really on tightness.

 

[Resu]

I think you'd be more likely to snap the head off the screw than majorly damage the tails

 

[Andy78]

I'm very surprised you are not trained with and issued a torque driver in your job.

 

[Darkwood]

Meters are usually grub screws with flat bases or slightly oval, this reduces the chances of damaging the conductors, often in connector blocks or even sockets and switches you with find the grub screws are sometimes pointed, this often leads to damage and shearing of conductors in part or full to the unaware.

I see burnt out sockets all the time from terminals and quite often its not loose but simply because the grub has chomped through half the strands or nearly through the solid conductor.

 

[Flipsy]

Meters are usually grub screws with flat bases or slightly oval, this reduces the chances of damaging the conductors, often in connector blocks or even sockets and switches you with find the grub screws are sometimes pointed, this often leads to damage and shearing of conductors in part or full to the unaware.

I see burnt out sockets all the time from terminals and quite often its not loose but simply because the grub has chomped through half the strands or nearly through the solid conductor.

Interesting never knew this so should be fine with tightness in meters then with them being flat. I’ve pulled cables out before to check damage and they do get very dented under tightening.

 

[Flipsy]

I'm very surprised you are not trained with and issued a torque driver in your job.

It’s something I’m going to push for in our team meetings because I think a lot of guys myself included are told to go as tight as you can. As that’s better than not tight enough. But a modular screwdriver creates a lot of torque.

 

[Flipsy]

I think you'd be more likely to snap the head off the screw than majorly damage the tails

Yup done that a few times in the past

 

[James]

That is really scary, you guys are trained to fir electrical meters, the device that has the highest current passing through it and have not been given instruction on how tight the terminals should be? the detail should be in the Mi for the meter in question. and I would have thought that a preset torque driver used to tighten the terminals.

 

[Darkwood]

Tails to meters are more often than not stranded which allows the cores to shuffle and flatten out a bit, usually leaving a grub screw footprint but as long as they are not cut into or playing up the sides of the grub where poor design leaves a gap then you should be fine.

Think about crimping a stranded cable and a solid cable, the crimper used are often different, indented for solid are common and shaped/pressed crimps for stranded.. this account for how the cores behave when crimped, if you use the wrong one for the cable it can cause a bad joint or damaged crimp/cable.

 

[Dustydazzler]

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

 

[Pete999]

Suitable tools yes but no info really on tightness.

No torque tools then bunch of idiots, that would be my first option, know wonder there are fires etc.