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Topic Title: Bolting earths to metal enclosures
Topic Summary: SWA especially
Created On: 24 July 2015 12:17 PM
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 25 July 2015 07:59 PM
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Baldyhugh

Posts: 353
Joined: 01 June 2007

Hi Andy

Yes however we are not referring to bonding here, but earthing. Unbroken bonding conductor would be more relevant where bonding cable was looped unbroken between say water, gas pipes etc where a plumber could Remove a bonding cable whilst doing work and not reconnect it. If the conductor is installed in an unbroken fashion then the other pipes or whatever remain bonded. However as I said we are referring to earthing here not bonding. The swa armour and enclosure requires earthing not bonding so I don't believe that it is necessary for the swa earth to remain continuous right to the met
 25 July 2015 08:05 PM
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sparkingchip

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I was trained to doing things as a matter of good practice without being able to back up the why by quoting a regulation, once you start doing things for no apparent reason they can become habit and just some thing you generally do.

Andy
 25 July 2015 08:27 PM
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Baldyhugh

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Ok Andy I take your point but what I and I'm sure you are aware is that many sparks do the same job in different ways. If you do yours that way as I said before it has the desired outcome, I just go about the same job in a different way and mine also has the desired outcome. What I was trying to get at was did you see any reason why mine was wrong or flouted any regulation? The part about the earth having to remain unbroken puzzled me slightly as it is neither a bonding conductor or a main earthing conductor.
 25 July 2015 08:29 PM
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perspicacious

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Hi Bod, I like their low profile look on the outside of a box and there's something about the way the square nut digs in that I like.
I wouldn't have thought the shape of nut/ bolt, if it's providing a secure connection would be high on the list of commonly encountered SWA problems?


What tensile grade are gutter bolts WB?

I've yet to see 8.8 on a gutter bolt and if you extol the virtue of the square nut digging in, what sort of screwdriver are you using that fits in the slot that must be all of 2 mm deep or is it the "I'll tighten it with a hammer & chisel" approach?

Regards

BOD
 25 July 2015 08:46 PM
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weirdbeard

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Originally posted by: perspicacious



What tensile grade are gutter bolts WB?


No idea



I've yet to see 8.8 on a gutter bolt and if you extol the virtue of the square nut digging in, what sort of screwdriver are you using that fits in the slot that must be all of 2 mm deep or is it the "I'll tighten it with a hammer & chisel" approach?[IMG][/IMG]


Big flat screwdriver and pliers but not hit, unlike locknuts, bushes etc

-------------------------
:beer)
 25 July 2015 09:15 PM
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leckie

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Well a big flat screwdriver and a pair of pliers is not likely to give a satisfying feeling of tightness. But it's a difficult think to judge. A couple of spanners can give a feeling of confirmed tightness! But these things are all subjective. However, let's not go along the path of torque settings. We all know when something is tight don't we?

I have a big cardboard box full of brass nuts, bolts, washers and bits of threaded bits of brass rod. When I crank them onto and earth connection I reckon it will stay put for the duration of my time on the planet. It was left in my work unit by the previous occupant, another sparks, so some of the bits are 30-40 years old!
 25 July 2015 09:28 PM
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Baldyhugh

Posts: 353
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Hi folks
If you read back a few replies I was asking for others methods for banjo bolting swa cable. Do you bolt through the crimped lug then through the banjo then through the enclosure with a lock nut on the outside? Or do you bend the banjo back like you would do on a plastic enclosure and bolt your cable to the banjo without going through the enclosure? Also regarding the bolt, I have seen some where the bolt goes through the enclosure then a nut on the inside then the lugged cable then another nut. I never liked this arrangement as a good connection relies on both nuts being tight whereas I prefer the lugged cable to be bolted in direct contact with the banjo rather than through another nut. All opinions welcome

Peter
 25 July 2015 09:31 PM
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sparkingchip

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Hands up who uses a torque wrench as well as a torque screwdriver when installing consumer units, distribution boards and the like.

Andy
 25 July 2015 09:32 PM
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sparkingchip

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Originally posted by: Baldyhugh

Ok Andy I take your point but what I and I'm sure you are aware is that many sparks do the same job in different ways. If you do yours that way as I said before it has the desired outcome, I just go about the same job in a different way and mine also has the desired outcome. What I was trying to get at was did you see any reason why mine was wrong or flouted any regulation? The part about the earth having to remain unbroken puzzled me slightly as it is neither a bonding conductor or a main earthing conductor.


Why use the core as a cpc in the first place?

Andy
 25 July 2015 09:37 PM
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sparkingchip

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One alternative arrangement to Banjos are Piranhas

I have some on the van as stock, but tend to use the supplied Banjos.

Andy
 25 July 2015 09:39 PM
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perspicacious

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I've found three instances of where the brass bolt on the standard issue 3/8" electrode clamp has sheared off letting loose the earthing conductor connection to float freely inside the box leaving the installation without an earth connection.

Only two sheared brass bolts on "banjos" but hundreds of loose connections where gutter bolts have been used......

Regards

BED
 25 July 2015 09:39 PM
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Baldyhugh

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Andy

I always use three core swa for single phase circuits. Most wholesalers don't even stock two core any more
 25 July 2015 09:42 PM
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Baldyhugh

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Originally posted by: perspicacious

I've found three instances of where the brass bolt on the standard issue 3/8" electrode clamp has sheared off letting loose the earthing conductor connection to float freely inside the box leaving the installation without an earth connection.



Only two sheared brass bolts on "banjos" but hundreds of loose connections where gutter bolts have been used......



Regards



BED
 25 July 2015 09:43 PM
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perspicacious

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I always use three core swa for single phase circuits. Most wholesalers don't even stock two core any more

Most don't stock 5 core SWA so how do installers manage on a TP&N job?

Regards

BED (definitly now I've had a bottle of Dog and 9 hours changing control gear on 36 T8 fittings today)
 25 July 2015 09:46 PM
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weirdbeard

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Originally posted by: leckie

Well a big flat screwdriver and a pair of pliers is not likely to give a satisfying feeling of tightness. !


Get a grip

-------------------------
:beer)
 25 July 2015 09:48 PM
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Baldyhugh

Posts: 353
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Originally posted by: Baldyhugh

Originally posted by: perspicacious



I've found three instances of where the brass bolt on the standard issue 3/8" electrode clamp has sheared off letting loose the earthing conductor connection to float freely inside the box leaving the installation without an earth connection. [IMG][/IMG]

Bod

Had that myself recently fitting an earth spike where clamp snapped off whilst tightening as as such I never fit brass bolts to banjos as they cannot be tightened up adequately in my opinion. Various other posts on this forum have said that the perception that brass bolts should be used both banjos to avoid the dissimilar metal issue is not accurate. I therefore use standard hex bolts and lock nuts





Only two sheared brass bolts on "banjos" but hundreds of loose connections where gutter bolts have been used......







Regards







BED
 25 July 2015 09:53 PM
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Baldyhugh

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Bod

Before you hit the hay are you actually saying that I should have used two core swa instead of three core for this job??? Common consensus with anyone I have spoken to is that three core swa for single phase circuits is the norm
 25 July 2015 10:17 PM
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leckie

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What Bod is saying is that the armour is fine for the CPC. If it were not what do you do on a TPN job?

That's not to say that there is anything wrong with using a core as a cpc, but it is not in any way generally a requirement.
 25 July 2015 10:23 PM
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sparkingchip

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Originally posted by: Baldyhugh

Andy



I always use three core swa for single phase circuits. Most wholesalers don't even stock two core any more


Same answer as I would give
 25 July 2015 10:27 PM
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Baldyhugh

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Leckie

What I was saying was that I always use three core for single phase but is not as widely stocked any more. It is virtually the same price as two core so in my opinion it's a no brainer to use three core. What about yourself, how do you bolt your banjos if you read my question a few replies back
IET » Wiring and the regulations » Bolting earths to metal enclosures

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