Roofing Bolts as Earthing studs

[jim1976]

Hi, all

Can anyone send me or direct me to website that as info on using roofing bolts for earthing stud ?

I work in a factory that is using the SWA for earthing (which I know is ok but with the bad glanding not so sure) and all banjo,s are held down with roofing bolts, now I worked at a power station for 2 1/2 years and this was a big no no due to the metal reacting and making bad earth connections. the boss here wont have it so need proof they need changing.

cheers

Jim

 

[Silly Sausage]

Googling "Bimetallic (galvanic) corrosion" should throw up something you can use.


This looks like a good introduction to the subject...
http://www.google.co.uk/url?sa=t&rc...sg=AFQjCNF-J3K0DspfUJxLitwO3LuXc8-M8Q&cad=rja

 

[telectrix]

never had a problem. it's brass to steel, so what. the brass of the gland is in contact with the steel armour anyway. if the atmosphre was damp/corrosive, then that steel would corrode anyway.

 

[shanky887614]

if he is a moaning bugger ask him to order in brass bolts and nuts, banjo's are brass afterall

 

[telectrix]

and after some hairy-arsed industrial spark has sheared off a few, he'll go back to roofers, which i hate for this purpose simply because they have heads designed so as to not fit any screwdriver known to man. far better to use hex nuts and bolts.

 

[shanky887614]

and after some hairy-arsed industrial spark has sheared off a few, he'll go back to roofers, which i hate for this purpose simply because they have heads designed so as to not fit any screwdriver known to man. far better to use hex nuts and bolts.

have you never used pozi head roofers?

 

[jim1976]

Googling "Bimetallic (galvanic) corrosion" should throw up something you can use.


This looks like a good introduction to the subject...
http://www.google.co.uk/url?sa=t&rc...sg=AFQjCNF-J3K0DspfUJxLitwO3LuXc8-M8Q&cad=rja

after looking at the table it would appear that they don't corrode together. does it make them the right thing for earthing tho ???

 

[telectrix]

their purpose is to connect to steel, so they're fine in that respect.

 

[telectrix]

have you never used pozi head roofers?

never seen them. just them with the cross slots.

 

[shanky887614]

never seen them. just them with the cross slots.

 

[Rockingit]

I have a love/hate with this subject. I use brass for the job whenever possible, simply as it stops people from moaning, but there's a back-up box of roofers in the van for when I run out. But I have still yet to see anything to convince me that to use galvanized steel is 'wrong'. For a start, it's a heck of a lot cheaper than brass!!!

 

[shanky887614]

I have a love/hate with this subject. I use brass for the job whenever possible, simply as it stops people from moaning, but there's a back-up box of roofers in the van for when I run out. But I have still yet to see anything to convince me that to use galvanized steel is 'wrong'. For a start, it's a heck of a lot cheaper than brass!!!

should be using bolts instead of roofers anyway.

roofers are pressed heads, bolts are machined or whatever.

in otherwords, ive seen a lot of rooferd with the heads sheared off but 8mm bolts, never

 

[krisfire09]

A good tool for roofers is a Phillips with a bit of the end sawn off, works a treat on the roofers with a cross on the head

 

[shanky887614]

A good tool for roofers is a Phillips with a bit of the end sawn off, works a treat on the roofers with a cross on the head

should be using a pozi2 mate instead of a philips.

why is there so many different types anyway?

ph0,1,2,3
pz0,1,2,3
then
phg etc who carries all these bits with them honestly?

 

[krisfire09]

Yea that's the one pal , il still be getting the different shapes and sizes confused in 10 years time

 

[Andy78]

should be using a pozi2 mate instead of a philips.

why is there so many different types anyway?

ph0,1,2,3
pz0,1,2,3
then
phg etc who carries all these bits with them honestly?

Me.
I have PZ0,1,2 and 3 in VDE drivers in my main box. Around a hundred different heads of all sorts that fit in my ratchet driver, PZ, PH, Torx, Allen, small sockets etc, and also a full set of security bits. Hardly takes up any space at all and invaluable sometimes.

I have always found the best tool for roofing bolts is your largest flat driver.

 

[shanky887614]

Me.
I have PZ0,1,2 and 3 in VDE drivers in my main box. Around a hundred different heads of all sorts that fit in my ratchet driver, PZ, PH, Torx, Allen, small sockets etc, and also a full set of security bits. Hardly takes up any space at all and invaluable sometimes.

I have always found the best tool for roofing bolts is your largest flat driver.

I have pz0,1,2. ph0,1,2 in vde
torx drivers as well and the usual multi bit sets a long with my trusty rachet set

 

[guest119]

Me.
I have PZ0,1,2 and 3 in VDE drivers in my main box. Around a hundred different heads of all sorts that fit in my ratchet driver, PZ, PH, Torx, Allen, small sockets etc, and also a full set of security bits. Hardly takes up any space at all and invaluable sometimes.

I have always found the best tool for roofing bolts is your largest flat driver.

Yep, everybody has a big yellow or a big red which occasionally needs a look at a grinder.

Boydy

 

[jaypp]

I have always found the best tool for roofing bolts is your largest flat driver.

20 pence piece and pliers/grips anyone?

 

[Rockingit]

Just out of interest, what are people using to bolt tray together with?

 

[shanky887614]

Just out of interest, what are people using to bolt tray together with?

tray couplers and 12mm roofers

 

[High Tower]

tray couplers and 12mm roofers

Same here

 

[Rockingit]

Hmmm..... That's what I thought. So we're happy to trust them for earth continuity of one thing, but not another?

 

[Engineer54]

As far as i remember, all construction/containment type bolts on this project is spec' stipulated to be stainless steel, can't remember the minimum grade mind... Same goes for specified electrical connections, eg,.... bolts/washers/ and nuts, all Stainless steel

 

[High Tower]

Hmmm..... That's what I thought. So we're happy to trust them for earth continuity of one thing, but not another?

No I'd be happy to use them to bolt up a banjo if that's all I had

 

[Rockingit]

So, that then HAS to beg the question of why is it that we get hung up over using Brass and also paying through the nose for it?!

 

[davesparks]

Hmmm..... That's what I thought. So we're happy to trust them for earth continuity of one thing, but not another?

Cable tray isn't required to have any earth continuity, or even be bonded.
Whereas the connection to the banjo is a connection of the CPC.

 

[guest119]

Cable tray isn't required to have any earth continuity, or even be bonded.
Whereas the connection to the banjo is a connection of the CPC.

So its not an exposed conductive part then?


Boydy

 

[Risteard]

So its not an exposed conductive part then?

No. You can't run unsheathed singles on cable tray.

 

[Engineer54]

Cable tray isn't required to have any earth continuity, or even be bonded.
Whereas the connection to the banjo is a connection of the CPC.

We test to confirm that all cable tray/cable basket/cable ladders etc, possess suitable earth continuity values throughout their length. I can't recall a single project that i've been involved on that hasn't called for earthed continuity of any of it's metal containment systems.

 

[Rockingit]

Cable tray isn't required to have any earth continuity, or even be bonded.
Whereas the connection to the banjo is a connection of the CPC.

Sorry mate, have to disagree!!

From the BEAMA (BS EN 61537) guide:

"2.10.2 Electrical continuity
Cable ladder and cable tray systems that are electrically conductive should have
adequate electrical continuity to ensure equipotential bonding and connections to earth.
Installations shall comply with the requirements of BS 7671 (The Wiring Regulations)."

 

[High Tower]

I bond every tray installation that I do!

 

[Rockingit]

I bond every tray installation that I do!

Likewise. Tray/Ladder/Basket..... I think the only thing I'd say doesn't need it is cable hooks for temporary looms (found mostly in entertainment and TV world for getting looms inside>out to OB trucks and the like).

 

[telectrix]

No. You can't run unsheathed singles on cable tray.

the reason for that is because tray is not an enclosure whereas trunking is. the tray is still an exposed conductive part of the installation.

 

[Guest77]

I agree with all of Rockins posts in this thread, just to add my views.

 

[Lucien Nunes]

To make a reliable connection you need the contact surfaces to be clean, flat, mechanically secure and gas-tight, which means the fasteners ought to be well made, with flat surfaces and effective threads that provide a definite minimum clamping force for a given tightening torque. Roofing bolts are not made to the same spec as hex set screws and I don't trust them to achieve this. The compromise design of the head makes it difficult to torque up accurately and the large diameter makes it easier for movement of the lug to rotate it and loosen the connection.

N/P brass hex for me every time for banjos and cable lugs, BZP steel bolts on tray & trunking where all surfaces are galv anyway.

 

[davesparks]

Sorry mate, have to disagree!!

From the BEAMA (BS EN 61537) guide:

"2.10.2 Electrical continuity
Cable ladder and cable tray systems that are electrically conductive should have
adequate electrical continuity to ensure equipotential bonding and connections to earth.
Installations shall comply with the requirements of BS 7671 (The Wiring Regulations)."

Interesting, I used to insist on all tray and basket being bonded until i was advised otherwise on a forum.

I'll offer up guidance note 8 item 10.11 on page 157 as evidence for my post above.

 

[Risteard]

the reason for that is because tray is not an enclosure whereas trunking is. the tray is still an exposed conductive part of the installation.

I know the reason is because it does not contain the cables - hence is a cable support rather than containment. However, as it cannot have unsheathed cables it is not an exposed conductive part. Usually jobs require cable tray to be earthed so generally it is done, however it wouldn't be correct to state that there is a requirement to do so.

And indeed there could be arguments as to why it shouldn't be.

 

[telectrix]

what about lidded tray?

 

[sparks1234]

So
We all install bolts and banjo's
but
do we all install a cable down to the earth block inside the dis board?