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

 

[newfutile]

Someone would have to effectively sink the trip current (usually upwards of 20mA) if they are insulated from earth with shoes /wood/carpet if would be quite difficult to achieve (luckily)

 

[stevethesparks]

If you are going to bond the studwork at a particular point, are you also going to put a link where every piece of stud /structure is jointed/not continuous? As already said, not necessary.

 

[UNG]

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!

If the studs are not fixed to the ceiling or floor how does the wall not fall over or move

 

[SparkySy]

The studs in all the metal walls I have seen just stand In the slotted floor and ceiling rails. The studs remain free floating until the Plasterboard is screwed into the uprights this then fixes the uprights in position. The only ones that are fixed are the ones at the wall ends and floor and ceiling rails!
here is a vid.

 

[grandfortune]

The stud this company use are stapled together or if they haven't got that tool they screw the uprights with drying screws so wall will,just need bonding from one point , looks like I'll be using metal noggins .

Thanks for the advice guys .

 

[i=p/u]

If you are going to bond the studwork at a particular point, are you also going to put a link where every piece of stud /structure is jointed/not continuous? As already said, not necessary.

Make the person shocked feel better

 

[UNG]

The studs in all the metal walls I have seen just stand In the slotted floor and ceiling rails. The studs remain free floating until the Plasterboard is screwed into the uprights this then fixes the uprights in position. The only ones that are fixed are the ones at the wall ends and floor and ceiling rails!
here is a vid.

That is the first time I have seen a metal stud wall built that way and not sure it would stand up to much real world abuse without flexing and cracking at the joints

So the plasterboard is fixed every 300mm to the uprights but not to the top an bottom rails where there is a sizeable area of board that remains unfixed as the fixings in the uprights look to fall 100 - 150mm short of the top and bottom of the plasterboard

Why not add a screw to fix the board, the upright and the top or bottom rail for continuity all it would need then is a skirting board fixed with screws into the metalwork at a few points and they could labelled "bonding test point" for more integrity even add the odd picture hook at an upright and label that as well ??.
When it comes down to it if it is necessary to maintain continuity then it wouldn't be out of order to ask the wall fixers to adapt their methods to ensure a level of metal to metal continuity is maintained at the top and bottom rail

This supplementary bonding is easy!!! problem what problem if there is a metal stud wall that needs to be tested then a few small screws above the skirting into the metal stud would provide test points that could easily filled with some decorators caulk afterwards

 

[SparkySy]

It's all done very fast no messing around putting noggins in and the likes! What is this screwing skirting board on they just use no nails on most of the jobs I've been on?
Yes it would be better if they screwed the boards top and bottom to the rails for a bit more strength some I have been on they have put some token ones in! And height wise sometimes they are just too tall for a sheet so an infill of board is used! Most of the boards are feathered out at the edges, to give enough depth for scrim tape on the joints then about 5-6mm of board fill about 100mm wide to hide the joints and that is it. No real plastering done as the board is finished apart from the edge for painting! Throw it up and onto the next one!!
I much prefer timber studs myself, way stronger!
Sy

 

[telectrix]

I much prefer timber studs myself, way stronger!

timber studding.Pfff! .what we need is bricks. proper walls.

 

[SparkySy]

I much prefer timber studs myself, way stronger!

timber studding.Pfff! .what we need is bricks. proper walls.

You'll be lucky, that's sooo yesterday!

On another note there is a huge new development going on fairly near me and some of the project consists of off site manufactured house units all pre plumbed and wired then lifted into position and bolted together. First time I have seen them used and quite interesting the speed they go together!