Torque Talk

[slartybartfast]

Happens at moderate temperatures, especially when stranded cables have been tinned with solder. That is why they shouldn't be tinned.

Doesn't necessarily need such high temperatures for it occur.

Ferrules on stranded cables will be mandated in regs before long for sure !

 

[DPG]

Ferrules on stranded cables will be mandated in regs before long for sure !

I think they are mentioned in the regs for fine stranded wires aren't they?

 

[pc1966]

I think they are mentioned in the regs for fine stranded wires aren't they?

Not exactly, but 526.9.1 says the ends have to be "suitably treated" and ferrules are one way to do that. The other common way is the ultrasonic weld you see on some RCBO neutral tails that are fine-stranded.

Also that section (526.9.2/3) say no to tinning conductors for screw terminals, etc.

Soldering is great though if it is actually the means of connection!

 

[pc1966]

hmmm....if temperatures are getting high enough to that then cable is likely undersized

It is more the cycling of hot/cold you get with time-varying loads or, to a lesser degree, just from day/night temperature changes, etc.

 

[Rockingit]

Not exactly, but 526.9.1 says the ends have to be "suitably treated" and ferrules are one way to do that. The other common way is the ultrasonic weld you see on some RCBO neutral tails that are fine-stranded.

Also that section (526.9.2/3) say no to tinning conductors for screw terminals, etc.

Soldering is great though if it is actually the means of connection!

Indeed, but who in their right mind gets out the soldering iron station when it takes 2s to put a ferrule on?!

 

[Lucien Nunes]

In the days before ferrules were widely known outside the panel-building industry, it was quite a popular albeit misguided pastime. For example, we saw a number of small theatre lighting installations with a plug patch at the dimmers, where the flexible patch cords were tinned before connecting to the conduit cables via normal terminal block. Someone obviously tinned their way along the line of them making each and every connection a loose one.

 

[pc1966]

As above, was quite common and obviously enough for it to be added to the regs as a no-no.

Ferrules are quite a neat way of helping fine stranded wire, and occasionally I have put them on coarse stranded if it is a big screw terminal instead of cage-clamp, etc, as I have seen wires removed and looking worryingly tin and flat as a result.

 

[Other_Tucker]

I'm all for the correct tightness in theory, it winds me up when colleagues use impact drivers to tighten (permanently weld) screw connections in CU's. I'd bet the correct, recommended torque, is less than normal wrist driver tightness.

If it becomes mandatory bureaucracy, how long until you need a calibration certificate for your torque screwdriver.

 

[Rockingit]

As above, was quite common and obviously enough for it to be added to the regs as a no-no.

Ferrules are quite a neat way of helping fine stranded wire, and occasionally I have put them on coarse stranded if it is a big screw terminal instead of cage-clamp, etc, as I have seen wires removed and looking worryingly tin and flat as a result.

You only have to fix one and then take it out again to see where the screw clamped down and all the strands it missed!

 

[DPG]

I'm all for the correct tightness in theory, it winds me up when colleagues use impact drivers to tighten (permanently weld) screw connections in CU's. I'd bet the correct, recommended torque, is less than normal wrist driver tightness.

If it becomes mandatory bureaucracy, how long until you need a calibration certificate for your torque screwdriver.

You should have it calibrated regularly already.

 

[pc1966]

You should have it calibrated regularly already.

Or at the very least store it wound to minimum setting.

 

[Dustydazzler]

I'm all for the correct tightness in theory, it winds me up when colleagues use impact drivers to tighten (permanently weld) screw connections in CU's. I'd bet the correct, recommended torque, is less than normal wrist driver tightness.

If it becomes mandatory bureaucracy, how long until you need a calibration certificate for your torque screwdriver.

The amount of Sparks I see using their 18v impact to do a consumer unit change grinds my gears , that hammer impact action on all the connections can't be good for them. I have no idea how many NM the average Dewalt 18v Impact driver delivers but I bet its more than the desired torque needed for the average MCB or RCBO terminal.

Just looked at some of the MI and some 18v impact drivers can deliver up to 1800NM of Torque yet many Sparks think this is an acceptable tool to make CU connections

 

[mainline]

The amount of Sparks I see using their 18v impact to do a consumer unit change grinds my gears , that hammer impact action on all the connections can't be good for them. I have no idea how many NM the average Dewalt 18v Impact driver delivers but I bet its more than the desired torque needed for the average MCB or RCBO terminal.

Just looked at some of the MI and some 18v impact drivers can deliver up to 1800NM of Torque yet many Sparks think this is an acceptable tool to make CU connections

I haven't long bought a bosch go screwdriver, I've only used it to tighten up some kitchen doors so far

 

[Dustydazzler]

Is Setting your Torque screwdriver to the highest setting and using it as a normal screwdriver Bad for it ? Will months and months of it being set to the highest setting eventually mess with the Lower settings ?

 

[mainline]

Is Setting your Torque screwdriver to the highest setting and using it as a normal screwdriver Bad for it ? Will months and months of it being set to the highest setting eventually mess with the Lower settings ?

Yes

When storing a torque wrench for an extended period of time, always wind it down to the minimum scale setting and not to zero

 

[littlespark]

Is Setting your Torque screwdriver to the highest setting and using it as a normal screwdriver Bad for it ? Will months and months of it being set to the highest setting eventually mess with the Lower settings ?

Are you saying you’ve ran out of normal screwdrivers?

 

[Dustydazzler]

Are you saying you’ve ran out of normal screwdrivers?

Not at all , I love a Screwdriver and still have my old CK set and old WIha set in my every day carry bag

But I have 2 Vde torque sets that see the light of day maybe once a month and I have considered just ramping up to the highest torque and just using them as normal everyday drivers

 

[mainline]

Are you saying you’ve ran out of normal screwdrivers?

Using it as a screwdriver without going over the torque setting shouldn’t do much harm, but hitting the setting and continuing to tighten, I wouldn’t have thought would do it any good.
I must admit I alway go over terminations again manually with a normal driver at the same time as giving the cable a wriggle near where it terminates doing it that way I sleep better

 

[mainline]

Not at all , I love a Screwdriver and still have my old CK set and old WIha set in my every day carry bag

But I have 2 Vde torque sets that see the light of day maybe once a month and I have considered just ramping up to the highest torque and just using them as normal everyday drivers

It’s ok if you can afford to waste them
I keep the torque set and bits for just that.

At least I known the bits aren’t worn away when I come to use it

 

[Dustydazzler]

Using it as a screwdriver without going over the torque setting shouldn’t do much harm, but hitting the setting and continuing to tighten, I wouldn’t have thought would do it any good.
I must admit I alway go over terminations again manually with a normal driver at the same time as giving the cable a wriggle near where it terminates doing it that way I sleep better

I do this ALOT and I know it makes using a torque driver a bit pointless but its just the way I'm wired

 

[pc1966]

I do this ALOT and I know it makes using a torque driver a bit pointless but its just the way I'm wired

Why not just go over a 2nd time with the torque driver?

That is what I tend to do as it helps avoid missing a fastener that was just done up lightly when assembling things and also allows for a bit of settlement. I guess it is also partly memory from mechanical devices where you do a set of fasteners up in different torque stages to avoid warping an assembly, etc.

 

[Marvo]

Wheel nuts and electrical terminals are different situations.

The torque value for the wheel nuts is set knowing exactly what is being fitted, what its made of etc etc.

Electrical terminals could have a range of types and sizes of conductor put in them, there may even be multiple conductors in there. I can't see how one universal torque setting can be correct for all sizes and types of conductor.

Here where I am the local regs limit the number of wires in any terminal or termination to two unless it was specifically designed to accept more. Do the UK regs allow multiple wires in a single termination point?

 

[davesparks]

Here where I am the local regs limit the number of wires in any terminal or termination to two unless it was specifically designed to accept more. Do the UK regs allow multiple wires in a single termination point?

Yes they do, there is technically no limit in the regulations. However common sense, good judgement and manufacturers instructions do need to be used.

On a standard ring final circuit in the UK you can expect up to 3 conductors in a terminal, the 2 legs of the ring and a spur.

Then there's split concentric cable where the neutral is made up of a dozen or so seperately insulated conductors which all get put together in the same terminal.

 

[littlespark]

You can bet the powers that be are taking notes…

“Hmmm. Limit each terminal to 3 conductors….?”

“So, new circuit… you can’t use maybe an existing spare mcb?”

“No no… has to be a new type breaker….. with um… new din rail type.. so new circuit means new board!”

Mr Hager: “sounds good to me”

 

[billyblade]

Just thought I'd throw in a few points here. Only skimmed the thread but hopefully, my input might help.

• Every torque screwdriver is sold with a calibration certificate. The standard they are manufactured to states that they should be calibrated every 12 months or 5000 clicks (whichever comes first). The first calibration should be carried out 12 months after first use. For the purposes of the standard, first use is taken as day of purchase so can be carried out 12 months from the date on the purchase invoice rather than the date on the supplied certificate.
• Yes, you should wind torque tools down to the minimum setting when not being used. This releases the tension on the spring and reduces the chances of it drifting out of range.
• A lot of breaker manufacturers are making the holes in their plastic casings too small to get the correct screwdriver down. Installers then resort to using the next size down and this is where breakages can occur., If you don't have a good fit between screwdriver bit/blade and screw recess then all the turning forces are concentrated on one or two surfaces instead of the multiple ones intended. In the case of the +/- blades you can actually get them 90 degrees out if you use one too small and that will almost inevitably cause breakage.
• A lot of breaker manufacturers are using poor quality screws where the fit is not good. This can cause blade breakage/ camming out/ screw damage etc.
• Some of the screws used look like they are intended for a +/- blade/bit but they are actually more suited to PZ or PH. If you have broken +/- blades in the past then try PZ or PH, see if they are a better fit in the screw. They tend to 'enter' the screw recess further than the +/- blades/bits.

 

[Dustydazzler]

blimey

I have had both my vde torque drivers for well over 4-5 years and neither have been re-calibrated yet

 

[DPG]

blimey

I have had both my vde torque drivers for well over 4-5 years and neither have been re-calibrated yet

Just think of all those terminations that might be done up to precisely the wrong torque!

 

[Dustydazzler]

Just think of all those terminations that might be done up to precisely the wrong torque!

Good job I check with my manual screwdriver after torquing

 

[mainline]

“So, new circuit… you can’t use maybe an existing spare mcb?”

Single conductor from mcb to a multi join. ?

 

[Other_Tucker]

I've invented a torque wrist calibrator, a small box with 10 screws on it each one lights up at the labelled torque. We can then verify our own hand power settings every morning.

 

[Megawatt]

I'm sure you could borrow someones torque screwdriver and self calibrate your wrist against it

I don't carry a torque screwdriver on site either but I have a range of very accurate versions in our workshop that are about 15 years old and too expensive to carry around. I'm thinking about getting one of these new snazzy looking red and yellow plastic ones although I wouldn't use it very often with the type of work I do. I'm just interested how they're used in the UK and what the recognised usage practices are now they've been popular for a while.

I found a great torque screwdriver and bought it from a company that sells firearms and it wasn’t expensive at all.

 

[Dustydazzler]

I've invented a torque wrist calibrator, a small box with 10 screws on it each one lights up at the labelled torque. We can then verify our own hand power settings every morning.

I theory you could buy one of those cheap torque check boxes and actually practice hitting certain torques with your wrist.

 

[Dustydazzler]

I found a great torque screwdriver and bought it from a company that sells firearms and it wasn’t expensive at all.

You can buy a normal torque screwdriver for as little a £10 on Ebay , the only issue is they are not Vde rated for the Uk

 

[mainline]

One of these maybe handy to have.

RS 663-904 Torque Analyser with 0-13 Nm / 0-120 lbf in - Calibrated | eBay

Find many great new & used options and get the best deals for RS 663-904 Torque Analyser with 0-13 Nm / 0-120 lbf in - Calibrated at the best online prices at eBay! Free delivery for many products.

www.ebay.co.uk

 

[netblindpaul]

Long time no see and I hope you're all doing well.

I see that torque screwdrivers have become the height of fashion in the UK over the last couple of years. I wondered what general practice has been adopted regarding their use.

Are electricians expected to;
Have a torque screwdriver on site at all times?
Check torque of all terminations in CU's / DB's they open or just any new terminations they make?
Check the torque of all terminations in any accessories they open?

Also;
Is acceptable to do torque testing live in a CU (assuming a VDE screwdriver)? Is a risk assessment required for live torque testing?
If torque testing is performed in a DB/CU do you just check screws for tightness or do you loosen off all terminations first then re-torque to the correct figure to eliminate overtightened connections as well as loose ones?

Scam members are expected to use a torque screwdriver for every termination to comply with the terms of their membership. What is done is another thing.

On an EICR, it might be expected to check terminations, but the requirements of an EICR are also minimum disturbance.

Any new terminations are expected to be completed with a torque driver; as I have said, this is a requirement of scam membership and is inferred in BS 7671.

It isn't a requirement to re-check every termination you come across.

It is not acceptable to torque terminations live unless this can be justified under the live working assessment in the law.
It is not reasonable to expect that it is necessary to do such a thing with the circuits energised.

To ensure that termination is at the correct torque, it is necessary to slacken it and then re-tighten it.
Hence, you are disturbing the connection, which is not good when doing an EICR.
Things could go wrong, or a latent defect could be introduced.

Such devices would need calibration in accordance with the screwdriver OEM instructions and/or any quality standards your company is working to.
Also, the scam membership requirements may have a calibration period.

The calibration period for a torque screwdriver would typically be annual.
Mind, if it fails, then you should strictly speaking revisit every connection made since the last calibration, like that is going to happen!
So, watch this space for the monthly check devices and scam requirements to check your drivers against the known source every month!

 

[Marvo]

If it's not acceptable to torque live terminations why would you even bother to get a VDE rated torque screwdriver, you could just use a normal mechanics version which I'm sure would be considerably cheaper.

I've bought one now to see what all the hate is about. There's none available over the counter here at any of our electrical wholesalers so I had to get it on Amazon and the shipping cost as much as the damn tool. There's also no calibration facitily available here so I won't be able to use it in real life for very long. The one I got is a Draper and it comes as a kit with various handles and interchangable blades which are obviously proprietary fitting and you can't use Wiha or Wera blades or standard 1/4 in bits in it.

 

[netblindpaul]

If it's not acceptable to torque live terminations why would you even bother to get a VDE rated torque screwdriver, you could just use a normal mechanics version which I'm sure would be considerably cheaper.

I've bought one now to see what all the hate is about. There's none available over the counter here at any of our electrical wholesalers so I had to get it on Amazon and the shipping cost as much as the damn tool. There's also no calibration facitily available here so I won't be able to use it in real life for very long. The one I got is a Draper and it comes as a kit with various handles and interchangable blades which are obviously proprietary fitting and you can't use Wiha or Wera blades or standard 1/4 in bits in it.

The H&S "bods" in the UK can't understand that people can work on isolated equipment without using insulated tools.
However, in their defence, the UK public distribution network is in such a poor state of repair that the PME/TN-C-S system using CNE/PEN conductors is breaking down and there are many more PEN failures than are reported.
A PEN failure can result in a rise in potential of N & E conductors, which could be unexpected and hazardous, to persons.
So then an insulated tool helps.

I once met a contractor that was thrown off site for not using insulated tools.
It was crazy really, yes, he was working in the main incoming DB, but, there was no supply to the building at the time!

 

[Dustydazzler]

Most Insulated hand tools really don't cost that much more than non-insulated hand tools.
A basic 6 piece Set of screwdrivers possibly costs a fiver more to buy them Vde rated.
I know we aren't supposed to work Live , but we all poke about in the odd board which is Live so is wise to use Vde rated screwdrivers

 

[richy3333]

Scam members are expected to use a torque screwdriver for every termination to comply with the terms of their membership. What is done is another thing.

On an EICR, it might be expected to check terminations, but the requirements of an EICR are also minimum disturbance.

Any new terminations are expected to be completed with a torque driver; as I have said, this is a requirement of scam membership and is inferred in BS 7671.

It isn't a requirement to re-check every termination you come across.

It is not acceptable to torque terminations live unless this can be justified under the live working assessment in the law.
It is not reasonable to expect that it is necessary to do such a thing with the circuits energised.

To ensure that termination is at the correct torque, it is necessary to slacken it and then re-tighten it.
Hence, you are disturbing the connection, which is not good when doing an EICR.
Things could go wrong, or a latent defect could be introduced.

Such devices would need calibration in accordance with the screwdriver OEM instructions and/or any quality standards your company is working to.
Also, the scam membership requirements may have a calibration period.

The calibration period for a torque screwdriver would typically be annual.
Mind, if it fails, then you should strictly speaking revisit every connection made since the last calibration, like that is going to happen!
So, watch this space for the monthly check devices and scam requirements to check your drivers against the known source every month!

Which 'scam' are you referring to as I had my NICEIC annual assessment 2 weeks ago and he had no interest in asking about torque screwdrivers at all? We tested at a couple of CU's - continuity and insulation resistance. Removed cables were re-terminated in front of the assessor with no torque driver?

 

[netblindpaul]

Which 'scam' are you referring to as I had my NICEIC annual assessment 2 weeks ago and he had no interest in asking about torque screwdrivers at all? We tested at a couple of CU's - continuity and insulation resistance. Removed cables were re-terminated in front of the assessor with no torque driver?

When I was with the NIC my area engineer was happy that I had one, and that was the end of the conversation, but, it was a tick on his form.
Mind it was a few years ago, maybe the policy has changed, or perhaps my engineer was a bit more by the book.
I don't know.

 

[Dustydazzler]

I am tempted to use my 18v impact on the consumer unit tests on my next inspection

If questioned about the use of my 18v impact driver , my response will be 'well everyone else does it this way'

 

[pc1966]

Just had a reminder email from CEF about the coming calibration day in Dundee. Looked at the list and seems they don't offer torque driver cal as one of the services.

 

[timhoward]

Just had a reminder email from CEF about the coming calibration day in Dundee. Looked at the list and seems they don't offer torque driver cal as one of the services.

I'm starting to think that under the trade descriptions act they should stop calling them calibration days.
It's very rare to find anyone who is willing to actually adjust a device. My experience has been that they check against the manufacturers tolerances and it either passes or doesn't. If it doesn't they suggest sending it off for specialist repair.
I tried 3 different tester-days with that Megger 1552, on the 2nd two I told them upon arrive that "it isn't within spec, can you adjust it" and was told "No.". I'm looking forward to finding out whether my own efforts scrape through the system soon!

 

[ipf]

Just had a reminder email from CEF about the coming calibration day in Dundee. Looked at the list and seems they don't offer torque driver cal as one of the services.

Do they do 18v impact driver cal's?

 

[Dustydazzler]

Do they do 18v impact driver cal's?

This gezzer has mastered his own Cal test

 

[nicebutdim]

This gezzer has mastered his own Cal test

AvE has carried out some extensive tests on all manner of power tools - none survive, but he'll tell you which will be last to fail (or be pulled apart and never successfully reassembled).

 

[Marvo]

Well I've had my new torque screwdriver for a couple of weeks, I wanted to use it as much as possible to see why it's such an emotive issue. Unfortunately I work on control centres, everything from populating and wiring new panels in our workshop to sitework on panels of all ages... some of which are very old.

The first thing I noticed was very few components over a year or two old had a torque spec readily available for their terminations. Some maunfacturers were better than others, most of the Allen Bradley items had a spec if you were willing to comb through the individual spec sheets but much of the Indian, Chinese, Taiwanese or even USA manufactured items had no termination torque spec available whatsoever.

Second thing I noticed is how much work it is to torque check even a small control panel. Lack of spec aside, just the process of loosening all terminations and resetting them with a torque driver is helluva time consuming with the constant readjustment and changing of screwdriver tips. I did one very small panel, probably 5 or 6 years old that consisted of 9 or maybe 10 contactors and relays, a timer, a current relay and a few circuit breakers, a dozen pilot lights and maybe 25 DIN rail terminals and it took me over an hour. It was the first and last panel I did.

I could see their advantage in use for a domestic sparky working on new installs or CU changes or in a manufacturing environment. For existing installations I think with losening and retorquing they're not practical and just to retorque without loosening there's better, safer and more convenient alternatives to find poor connections such as careful visual inspection and thermal cameras.