Bonding metal studwork,

[grandfortune]

HI all,

I need to bond metal stud work on new build houses, 4mm from socket to an upright, uprights have roof baton for noggins, then socket screwed to the baton, does the bond need access for testing at all?

I'm looking into metal noggins for continuity,i think it will be better, just wondering if supplementary bonding needs access for testing or inspecting as it will be covered by the plasterboard?

Cheers
Grand

 

[Pete999]

HI all,

I need to bond metal stud work on new build houses, 4mm from socket to an upright, uprights have roof baton for noggins, then socket screwed to the baton, does the bond need access for testing at all?

I'm looking into metal noggins for continuity,i think it will be better, just wondering if supplementary bonding needs access for testing or inspecting as it will be covered by the plasterboard?

Cheers
Grand

Test it to see if it requires supplementary bonding

 

[robd]

But do you need to bond it?

 

[robd]

Would suggest you might need a sit down in a dark room before you seriously contemplate doing that

 

[cliffed]

Is it extraneous is it an exposed conductive part…NO… no need to bond.

 

[grandfortune]

Is it extraneous is it an exposed conductive part…NO… no need to bond.

Someone got a shock off it , not my job but another site , a plasterboard screw went into the live and the whole wall was live , had an email from building firm to bond wall from one socket . And here I am looking for solutions , don't know if the RCD tripped or anythinging else as to what happened.

 

[DPG]

Not sure how you are going to bond all the metal partition pieces and ensure the connections will be accessible for inspection!

I'd be working out why the RCD didn't trip.

 

[Pretty Mouth]

Someone got a shock off it , not my job but another site , a plasterboard screw went into the live and the whole wall was live , had an email from building firm to bond wall from one socket . And here I am looking for solutions , don't know if the RCD tripped or anythinging else as to what happened.

Regulations wise:

Unlikely that the stud work is an extraneous part (it's probably not imbedded in the ground), so doesn't need bonding. It's not part of the electrical system/equipment, so not an exposed conductive part, so doesn't need earthing. However, (other than the exceptions mentioned in 522.6.204), cables that pass through it need additional protection by 30mA RCD.

So, as what you're being asked to do is not required by the regs, I would say you can do it exactly as you see fit. I'm assuming the end result is to ensure that the protective device operates if there is a fault from live conductors to the studwork? If so, then it's earthing.

 

[Pretty Mouth]

Not sure how you are going to bond all the metal partition pieces and ensure the connections will be accessible for inspection!

I'd be working out why the RCD didn't trip.

At a guess, I'd say the studs are fitted to/on to dry building materials that don't give a good enough path to earth for it to trip

 

[DPG]

At a guess, I'd say the studs are fitted to/on to dry building materials that don't give a good enough path to earth for it to trip

Yeah maybe so. Enough current for a shock to be felt though. Be interesting seeing the actual fault.

 

[telectrix]

confiscate the boarders impact drivers and make them use all metal screwdrivers. then they'll know when they've hit a cable.

 

[grandfortune]

Thanks guys , u assumed the RCD tripped but I don't know much about it , builder rightly asked why it wouldn't trip straight away as this was a fault for about 6, months . I've been to look at a wall and can see it's not connected to the system at all and rightly so doesn't need bonding . They've asked for a bond strap from 1 socket to the track anywhere , witch sound reasonable , just wondering on the accessibility of that bond and does it need access to test . It will be all over boarded and skimmed hence no way if testing it

 

[westward10]

It needs to be accessible. It is a pointless exercise.

 

[UNG]

The death of Emma Shaw may be worth taking into account when deciding on whether to supplementary bond or not. I think I would at least bond to the sole plate of the stud wall if it is metal this would also bond the studs just as a bit of rear end covering. If you used something like the Walraven RSWB to mount your socket boxes then you have a direct metal bond to two of the studs and if the sole plate is metal you have got it covered.

I know the Emma Shaw case involved a number of events occurring that may not happen and never happen again but in this case they did an a life was lost

 

[cliffed]

Bit if a problem that,similar to when sheathing used with no direct contact with earth someone drills a hole catches the Live onto the metal sheathing.

 

[SparkySy]

It would be difficult to bond a metal stud wall as the metal stud drops are not usually mechanically fixed, screwed or bolted to the floor or ceiling plate they rely on the plasterboard to hold it all together so even if you did just bond the floor or ceiling plate it may not have a good connection to the studs imho!

 

[cliffed]

Yea just wondering why the Rcd didn’t trip…it’s gotta sense the unbalance if there is one…is it a TNCS Supply

 

[telectrix]

if the metal studding isn'tconected to earth (or anything else) ther will be no current flowso therefore no imbalance to trip the RCD, until somebody touches it snd provides the earth path.

 

[i=p/u]

So should be tagged too circuits within the wall.

 

[cliffed]

if the metal studding isn'tconected to earth (or anything else) ther will be no current flowso therefore no imbalance to trip the RCD, until somebody touches it snd provides the earth path.

Agree but the imbalance still should be detected by the RCD someone completing the circuit to earth would cause that imbalance between the Live conductors