Earthing a scaffold any suggestions

[chris day]

A local church is going through some refurbishment, it currently has a mass of scaffolding in one position.

I have been asked to earth it... my initial thinking would be TT spikes on all 4 corners?

 

[Spoon]

Not knowing a lot about this but is it the norm to earth scaffolding?

 

[Richard Burns]

I would have expected that the scaffolding should be bonded to the earthing system of the church and the lightning protection, if present; to earth the scaffold would be simply to ensure that if some had a shock from the scaffold it would be very serious rather than serious, though it might ensure an RCD's operation.
To bond you would need to ensure the scaffolding was electrically continuous and then run a suitably sized bonding cable from the scaffold (possibly at two places for reliability) to the MET / bonding or lightning protection.

 

[littlespark]

If it was a regular thing to do, there would be official products such as "scaffold bonding clamps" or something.
The construction of scaffold doesn't lend well to being an earthing conductor. Painted metal, slotted into each other.
The impedence between the top of the platform and where any main bonding could be too high to be of any benefit.

I cannot recall any mention in the BYB of earthing a scaffold

 

[Squid]

Its a Church, God will look after the scaffolding.

 

[westward10]

Here are the parts from BS7430.
They have come out in the wrong order, read 3, 2, 1 and 4.

 

[westward10]

It should be noted the above is from an old copy of BS 7430 but generally there are no changes from the above. It is no longer Reg 22 but Reg 8.

 

[Richard Burns]

Paragraph 8 Text as text:
8 Special installations
8.1 Temporary scaffolding and similar metallic structures
8.1.1 Metallic structures assembled by means of bolted joints or screw clamps
NOTE 1 Where structures are assembled using bolted joints or screw clamps a multiplicity of such connections is likely to provide several paths of relatively low resistance. Although such structures are not designed to be electrically continuous it is reasonable to assume that they have a low value of electrical resistance.
Whatever type of structural fastenings or footings in contact with the ground are employed and however a temporary structure may be fastened to a permanent structure, it should not be assumed that a temporary metallic structure is effectively earthed.
NOTE 2 Most erections of metallic scaffolding are the subject of statutory regulations concerning construction work.
The distribution of electricity on construction sites should conform to BS7375. Except where it is necessary for lightning protection purposes (see 8.2), scaffolding external to a structure should not be connected to the means of earthing within the structure that is afforded by supply authorities.
Where scaffolding is erected against or around a structure which does not have electrical services, and electrical equipment is not likely to be used for construction work, electrical bonding for shock protection purposes may be omitted.
Where protective conductors are required, they should be of copper and protected against corrosion by a covering at least equivalent to the insulation of a single non-sheathed cable, and should be routed to avoid damage from work equipment and work activities. A conductor should be connected to scaffolding by a corrosion-resistant clamp conforming to BS951, and which is suitably protected against mechanical damage. For extensive scaffolding structures, where earthed, connections should be made at points not more than 20 m apart laterally.
8.1.2 Structures forming part of precautions to avoid danger from live overhead electric lines
COMMENTARY ON 8.1.2
The Health and Safety Executive publishes guidance on the dangers of live overhead powerlines, see Guidance Note GS6 Avoidance of Danger from Overhead Electrical Lines[5].
Paragraph 20 b) of GS6 refers to the use of a tensioned wire fence as a high level barrier, and notes that the electricity distributor has to be consulted about the erection and earthing of the barrier.

8.2 Lightning protection
If scaffolding is associated with an existing structure which has an external lightning protection system (LPS), it should be bonded to the earth termination network and the air termination network of the LPS. Lightning protection should otherwise be provided where indicated by risk assessment performed in accordance with BSEN62305

 

[Spoon]

I prefer the psychedelic waves that @westward10 posted...

 

[Squid]

I wonder if anything goes boobies up (are you allowed to use that word on here) the insurance company will say it was an "act of God"?

 

[Wilko]

If I recall correctly BS62305 covers lightning protection. And if the Church had protection deployed and was still damaged, then bet those lovely insurance folk would make a case that only God could defeat BS62305 so it's clearly an act of God, so no need to pay out ...

 

[Squid]

Stick the scaffold pole in the ground/earth, its earthed then isn't it?

All this faffing around with B-S Regs

 

[telectrix]

ere u go:

 

[DPG]

It was inevitable that tel would post a link to that song.

 

[Squid]

It was inevitable that tel would post a link to that song.

Care in the community allowed him access to the internet?

 

[GeorgeCooke]

Use bamboo scaffolding like they do in Hong Kong.

 

[ipf]

ere u go:

Give 'em green and yellow suits and there you go.

 

[elsparko]

Use bamboo scaffolding like they do in Hong Kong.

i watched a documentary about that stuff, amazing how high they can build with it

 

[Pete999]

i watched a documentary about that stuff, amazing how high they can build with it

Yeah, me as well, and the way the clmber about all over the bamboo with no fear.

 

[PEG]

Hi,who has asked you to "alter" this scaffolding?

The outfit responsible for erecting it,and whoever commissioned it,would or should have done a risk assessment,and any requirement to earth/bond or otherwise modify the structure,would be in that.

You cannot start clamping cables to a structure which at end of build up,and on a daily basis,should be inspected visually,to conform to exactly what was commissioned and agreed.

There could be a discussion regarding any unauthorised work,such as this,as introducing a potential electrical risk,where there was not one previously.

This is a common issue,with large,long-running refurbs,on churches,community halls,scout halls,etc,where "bob" on the committee,who did a bit of electrical work when working,mentions during a meeting,that there needs some "earthing",and he can sort it...

If i am wrong,i apologise,which means there is a request through specification,in which case,simply follow that directive.