Being over cautious?

[academy]

Hello all,
Posted this on the Napit forum but had no respite se despite lots of views so thought I would paste it on here.
Interested in your opinions
afternoon all,

after some opinions on a job I have been asked to price. Spoke with another NAPIT member and to be honest not sure if we are being over cautious.
The current set up is an absolute abortion and the new manager has come in and wants it sorted out section by section.
Have been asked to fit a sub board on a waste management site to provide power at the other end of site for some cabins and a couple of commando sockets. The existing supply is pme intake cupboarding with a 6 way TP&N DB supplying lighting, cabins and some plant. All cables run (left laying) surface in SWA. No RCD except on the sub boards inside the cabins.

I am planning on running a new supply from this DB through a duct in the road to other side of some gates and then clip along the fence (they may fit a split duct after) along to a new DB. From here, supply the new cabins and commando sockets in SWA. The commando sockets would have rcd protection at the socket end, the cabins would have it in their own DB.
Question is, should there be rcd protection on the cables feeding the new cabins and sockets? The cable will be visible, SWA, marker tape used but due to the nature of the enviroment should it be classed as a construction site? Thinking about putting a time delayed 300ma as main switch on new DB but then am I being over cautious? Its not a building site but there is a lot of plant movement. If I fit this, why not fit it at the original DB and protect that cable too? Then while Im at it do the existing cables need protecting too?
See what I mean

What the other Napit guy (and myself) believe is to go with the 300ma main switch on the new DB to cover my rear (as the site is deadly enough as it is, will post some pictures when I get time) but obviously this will be pushing the price up.

Dont even start me on the extending PME I have just thought of................


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[jumpin jax]

What are you expecting the RCD to protect? Life? I understand where you are coming from but for the cable to get damaged it would have to be a machine on rubber wheels to do it, it is protected by a PD. TT it at the cabin end, divorce the swa at supply and earth it all through the RCD and rod at the cabin. My opinion, others may differ

 

[Deleted member 9648]

I'd class it as a construction/demolition site myself as you state there is constant plant movement.....in which case all the information you require is contained within section 704 of bs7671.

 

[Farmelectrics]

im with wirepuller its a construction site to me

 

[academy]

Thanks for the replies so far, construction site was what I was thinking (along with the other guy) originally, just wasn't sure if I was being too cautious


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[vjsmarwick]

Maybe the regs shod have made its self clearer that construction site does not have to a place where there is construction but maybe a heavy plant site would cover it better. But I would certainly cover your own --- and make it too safe than too relaxed about it men in heavy plant are not known for taking much notice to the fact there are live wires around.

 

[SirKit Breaker]

I dont think you are being over cautious, the site is what it is, and dangerous to boot. As someone else has already said, plant drivers have little or no regard for anything at all, they believe they are invincible when they are playing with big boys toys.

You need to be overly cautious, and rightly so. The installation has to be robust for obvious reasons, and it will be expensive for your client. But get this wrong, and you can bet that your client wont hesitate to sue you when something goes wrong, and that is when the dreaded Electricity at Work Regs will come out, which will be used to beat you from pillar to post, it will then be your good self on the end of a large bill, or a stay in one of her majesties all inclusive resorts.

Cheers.........Howard