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Topic Title: Guidance on terminal torque
Topic Summary: Is there any?
Created On: 14 February 2013 06:03 PM
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 15 February 2013 09:59 AM
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NeilBush

Posts: 32
Joined: 21 December 2010

You've all sussed this between yourselves. Just a note to say that tamper evident stickers are already available:

http://www.elecsa.co.uk/shop/e...597-93a4-a00d00b44218

I have an interest in Wiha Tools UK

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I have an interest in Wiha Tools
www.wiha.com/england
 15 February 2013 10:45 AM
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tomgunn

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I give up!

-------------------------
Tom .... ( The TERMINATOR ).

handyTRADESMAN ... haha

Castle Builders

Why did Nick Clegg cross the road? Because he said he wouldn't!

I can resist anything..... except temptation! ( Karl Gunn ).
 15 February 2013 10:58 AM
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OMS

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Originally posted by: tomgunn

I give up!


Don't stress over the little things Tom, this was a procedure looking for a home - and now it's found one.

Pay no attention and crack on - you'll be having to apply a pressure gauge to your plastering trowel next - that'll stop you polishing up the fines no bother -

Regards

OMS

-------------------------
Failure is always an option
 15 February 2013 11:05 AM
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tomgunn

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Sound advice - as usual OMS! I'm happy again!

regards... Tom

-------------------------
Tom .... ( The TERMINATOR ).

handyTRADESMAN ... haha

Castle Builders

Why did Nick Clegg cross the road? Because he said he wouldn't!

I can resist anything..... except temptation! ( Karl Gunn ).
 15 February 2013 12:05 PM
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rocknroll

Posts: 8826
Joined: 03 October 2005

LOL You 2% of the electrical workforce who grace this forum day and night love the 'techno-paranoia' that is rampant, it is highly unlikely in laboratories or research centres such as ours I will come into work one morning to a car-park full of pallets of consumer units awaiting examination at a cost of £2.2k upwards.

99% of fires at the origin cut-out/consumer unit are attributed to overloading and tampering and this is accepted without further examination, the most common tool of electrical theft is a bit of old cord from a kettle or whatever, jam one end into the fuse blade and the other into the top of the main switch with a matchstick or cocktail stick, we were involved in one a short while ago and when the immersion which was on a timer came on at 4 o'clock in the morning the occupants who in this case were socially challenged and within the Methadone program awoke to a blazing hallway, lucky this time.

The majority of contractors who have used these items have reported that when checking with a screwdriver afterwards it still needed a quarter to half a turn to feel right, slightly defeating the object,
then thrown in the van only to be resurrected when a vigilant inspector is present.

What we have discovered is that problems like loose connections elsewhere in the system can cause MCB's to fail in a number of ways although generally a tell-tale sign of preceding chattering is often an indication of this, so are you going to torque all the accessories that are connected to your super duper torqued consumer unit.

Get a grip on yourselves.

regards

-------------------------
"Take nothing but a picture,
leave nothing but footprints!"
-------------------------
"Oh! The drama of it all."
-------------------------
"You can throw all the philosophy you like at the problem, but at the end of the day it's just basic electrical theory!"
-------------------------

Edited: 15 February 2013 at 01:05 PM by rocknroll
 15 February 2013 01:01 PM
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DR2366

Posts: 705
Joined: 09 April 2006

So is it just a case of a natural progression of manufactures to say this screw/fixing needs to be this tight?

They could put lots of clauses into their instructions which are easy to say but a pain to comply with. 3amp fuses and extract fans come to mind, but lets not go there on this topic.

A local training centre near me had a rep round selling torque screwdrivers saying that they are an essential item! But then he would say that wouldn't he.

Has anyone seen anything on the subject from the trade/consumer bodies?
 15 February 2013 01:21 PM
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NeilBush

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The IET recently reported on the HSE fire stats from terminal tightness on the early Smart Meter roll-out:

http://eandt.theiet.org/news/2...smart-meter-safety.cfm

-------------------------
I have an interest in Wiha Tools
www.wiha.com/england
 15 February 2013 01:28 PM
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rocknroll

Posts: 8826
Joined: 03 October 2005

There is nothing wrong with torque settings etc, they have their place and at the moment there millions of machines setting screws, nuts and bolts to the appropriate torque requirements, the anomoly is they are put in the hands of beings recruited from the 'human race' and as experience has taught us doomed to failure.

regards

-------------------------
"Take nothing but a picture,
leave nothing but footprints!"
-------------------------
"Oh! The drama of it all."
-------------------------
"You can throw all the philosophy you like at the problem, but at the end of the day it's just basic electrical theory!"
-------------------------

Edited: 15 February 2013 at 01:44 PM by rocknroll
 15 February 2013 01:59 PM
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DR2366

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So do we need to run down the shops and buy a torque screwdriver or not?

If we do perhaps we should band together and get a huge discount for a bulk buy!
 15 February 2013 02:17 PM
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dickllewellyn

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The choice is entirely yours dr2366. Personally, I have chosen to use a torque setting tool where a torque setting has been stated. I completely understand the counter argument too. But personally I also fuse extract fans, and I also make sure the tyres on my van are pumped up to what the manufacturers suggest.

If there is something I can do to ensure that I am covered if the worst should happen, then I am happy to do so. If I don't feel the need to do something, I won't do it. I climb rock faces, but I always make sure there is a rope, and that I know the belayer is experienced and trustworthy. I may fall of the rock, the belayer may not be paying attention, and I may plummet to my death. But if I've done everything in my power to minimise risk, I feel happier.

-------------------------
Regards
Richard (Dick)

"Insert words of wisdom and/or witty pun here"
 15 February 2013 03:15 PM
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tomgunn

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Originally posted by: dickllewellyn

The choice is entirely yours dr2366. Personally, I have chosen to use a torque setting tool where a torque setting has been stated. I completely understand the counter argument too. But personally I also fuse extract fans, and I also make sure the tyres on my van are pumped up to what the manufacturers suggest.



If there is something I can do to ensure that I am covered if the worst should happen, then I am happy to do so. If I don't feel the need to do something, I won't do it. I climb rock faces, but I always make sure there is a rope, and that I know the belayer is experienced and trustworthy. I may fall of the rock, the belayer may not be paying attention, and I may plummet to my death. But if I've done everything in my power to minimise risk, I feel happier.


What we used to have in this ruined island was choice / nay FREEDOM - freedom to express our own thoughts - freedom to do what comes naturally not to be bossed about by someone who, in all probability, has never seen a screwdriver - have the effrontery to actually come up with some stupid idea however illogical and then make it a law so the poor old sparks has one more ridiculous item to worry about! Good god man - can you not see how daft this is? You need to make sure that the screws are tight and you can do that by 'feel' like I 'feel' like screeeeeeeeeeeeeaming sometimes at lifes inability to see common sense - just because this bloke who thought this idea up didnt get his leg over the night before he thought 'I know - I'll take it out on the sparks - haha!'!

Tom .... and relaxxxxxxxxxxxxxxxxxx

-------------------------
Tom .... ( The TERMINATOR ).

handyTRADESMAN ... haha

Castle Builders

Why did Nick Clegg cross the road? Because he said he wouldn't!

I can resist anything..... except temptation! ( Karl Gunn ).
 15 February 2013 04:00 PM
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rocknroll

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Originally posted by: NeilBush

The IET recently reported on the HSE fire stats from terminal tightness on the early Smart Meter roll-out:

http://eandt.theiet.org/news/2...smart-meter-safety.cfm


But this relates to sloppy work practices not the issue of your targetting the construction related trades in the domestic sector, thousands of electricians go out there every day, take on risk, use their common sense and ability and do a good job, they use their practical ability in tightening up terminals and screws, its part of the game, issue them with a torque screwdriver and as I pointed out its the human race so they will not believe it and still check and tighten that extra bit until they feel its right therefore defeating the object.

Should a consumer unit come in for terminal torque setting that has been involved in an incident such as a fire it would be scientifically impossible to identify if this was the problem as most equipment when subject to extreme conditions as this take on a metamorphosis, terminals and screws could be loose or even welded tight, then you have the legal argument with the contractor swearing they tightened them up to torque and shifting the blame onto the manufacturer to determine whether the screwdriver was fit for purpose., meanwhile in the real world ..................................................

Statement:
You are in the business of sales, we are in the business of safety and there is no evidence of any trends that suggest you need to go out immediately and buy the said item, apart from those who need to satisfy the needs of their keen annual inspectors, but dont the scheme shops sell them as well.....................


I am the voice of the blind!!!!!!!!!!!

regards

-------------------------
"Take nothing but a picture,
leave nothing but footprints!"
-------------------------
"Oh! The drama of it all."
-------------------------
"You can throw all the philosophy you like at the problem, but at the end of the day it's just basic electrical theory!"
-------------------------

Edited: 15 February 2013 at 04:06 PM by rocknroll
 15 February 2013 04:22 PM
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rogerbryant

Posts: 863
Joined: 19 July 2002

Pure human nature! In a previous job the machine operators were given a torque wrench to tighten the head clamp on the extruder. Standard practice 'Pull until it clicked, then an extra pull to make sure it was tight' ;-)

Best regards

Roger
 15 February 2013 04:32 PM
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stateit

Posts: 2132
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Originally posted by: tomgunn

What we used to have in this ruined island was choice / nay FREEDOM - freedom to express our own thoughts - freedom to do what comes naturally not to be bossed about by someone who, in all probability, has never seen a screwdriver - have the effrontery to actually come up with some stupid idea however illogical and then make it a law so the poor old sparks has one more ridiculous item to worry about! Good god man - can you not see how daft this is? You need to make sure that the screws are tight and you can do that by 'feel' like I 'feel' like screeeeeeeeeeeeeaming sometimes at lifes inability to see common sense - just because this bloke who thought this idea up didnt get his leg over the night before he thought 'I know - I'll take it out on the sparks - haha!'!


Is this meant to be set to a crescendo of Parry's 'Jerusalem' Tom? Probably climaxing in volume and holding at that volume somewhere about 'You need to make sure...'



-------------------------
S George
http://www.sg-electrical.com
 15 February 2013 04:34 PM
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rogersmith7671

Posts: 886
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In the old black and white 625 lines days. Men where men and they had "fuse boxes" to match. it was possible to "lean in" on the buss-bar screws and get 'em nice and tight. These days that cannot be done because the cheap plastic MCB casing will warp and the buss-bar screw will "go on cocked" reducing the boards already moot 12k resilience to faults. Modern boards and MCB's need to be fitted with a level of precision that is proportional to their reduced fabric. Hence the torque requirement, designed to reduce the amount of pressure and stress on the poor quality stuff on sale now, so cheaply.
Regards.
 15 February 2013 04:36 PM
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rocknroll

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And now of course the science bit, looking at some of the manufacturers data they say a 'minimum' of 1.7Nm, for a human aged between 31-50 the mean wrist torque when using a screwdriver is (male - 4.48Nm) and (female - 3.89Nm) well tight eh!!!!!!!!!!

Never marry a woman with big hands, it makes you feel inadequate.

regards

-------------------------
"Take nothing but a picture,
leave nothing but footprints!"
-------------------------
"Oh! The drama of it all."
-------------------------
"You can throw all the philosophy you like at the problem, but at the end of the day it's just basic electrical theory!"
-------------------------
 15 February 2013 05:06 PM
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Legh

Posts: 3472
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Originally posted by: DR2366

So you have a torque wrench then?


Lol, There appears to be a lot of torque going on here

There's no point in having the tools if you don't know how to use them.
The first point to start might be knowing what the limits are and as you've stated, the values given are those that might be reasonably used as maximum values.

I often wonder how tight a connection should be. I start by tightening up and then to simmer for about 30 secs and then I manage to get another half turn.

I have never had one go loose on me yet - but then there is always a first time.........

Legh

-------------------------
Why do we need Vernier Calipers when we have container ships?

http://www.leghrichardson.co.uk

"Science has overcome time and space. Well, Harvey has overcome not only time and space - but any objections."
 15 February 2013 05:41 PM
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Jaymack

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Originally posted by: rocknroll
(male - 4.48Nm) and (female - 3.89Nm) well tight eh!!!!!!!!!!

The superiority is probably due to the Barclay's!

Regards
 15 February 2013 06:41 PM
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kj scott

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RnR has got this spot on, how many years have you been working without a torque screwdriver? How many terminals have you tightened? How many recalls have you attended due to connection failure?
The pseudo requirement for torque screwdrivers is no more than a sales scam for the gullible.

RnR can you direct us to written research that supports your very valid observations?

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http://www.niceic.biz
 15 February 2013 06:45 PM
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kj scott

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Originally posted by: NeilBush

The IET recently reported on the HSE fire stats from terminal tightness on the early Smart Meter roll-out:



http://eandt.theiet.org/news/2...smart-meter-safety.cfm


No mention of torque setting there though, just inadequate training.

-------------------------
http://www.niceic.biz
IET » Wiring and the regulations » Guidance on terminal torque

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