No RCD on entire installation

[sparky1508]

Hi all,

I have done a small job of installing a radial circuit and adding a spur to a ring final circuit.
I am not too sure about the existing installation. It is in a commercial premises office type with a single phase CU. I have an issue with the fact that there is not an RCD to be found. I think there should be one but I have done mainly domestic. Would it be possible to install a stand alone 30ma RCD before the CU or does it need a new CU. Please correct me if I am wrong.
Cheers

 

[Ian1981]

Hi all,

I have done a small job of installing a radial circuit and adding a spur to a ring final circuit.
I am not too sure about the existing installation. It is in a commercial premises office type with a single phase CU. I have an issue with the fact that there is not an RCD to be found. I think there should be one but I have done mainly domestic. Would it be possible to install a stand alone 30ma RCD before the CU or does it need a new CU. Please correct me if I am wrong.
Cheers

Does your new work require one cables buried in walls installing a socket for example?

 

[sparky1508]

Does your new work require one cables buried in walls installing a socket for example?

Yes, probably 1/3 of both ring final circuits is buried in the wall with plastic capping as I can see it coming out of the wall above the suspended ceiling. The rest is run round the perimeter of the office in plastic dado trunking with sockets.

 

[westward10]

Needed to undertake a risk assessment before works were carried as this requires a Minor Works.

 

[sparky1508]

I thought it was an EIC as I have installed a new circuit.

 

[Ian1981]

If you've installed a brand new circuit then it requires a eic

 

[westward10]

Thought it was from an existing circuit.

 

[Ian1981]

Yes, probably 1/3 of both ring final circuits is buried in the wall with plastic capping as I can see it coming out of the wall above the suspended ceiling. The rest is run round the perimeter of the office in plastic dado trunking with sockets.

If your cables you've installed are not in the wall then you might not need rcd protection for the cables anyway

 

[sparky1508]

Thought it was from an existing circuit.

The spur was from an existing circuit but I also reinstated an existing radial the had been disconnected by a previous spark. The reason it was disconnected was that they had floor sockets removed and the 2 MCB's labelled floor sockets were disconnected and removed. One of these had already been changed to a radial and was disconnected by mistake.

 

[westward10]

Commercial premises should have consulted client and carried out a risk assessment.

 

[westward10]

Not new circuits then.

 

[sparky1508]

This radial is directly below the CU. The ring final circuit I added a spur to has cables buried in the wall.

 

[Ian1981]

This radial is directly below the CU. The ring final circuit I added a spur to has cables buried in the wall.

Only the work you install needs to comply so if existing cables are in walls but the ones you install are not then you don't need an rcd for cables in the wall anyway.
If you want to improve the installation it's up to you and the paying client

 

[westward10]

Minor Works then, what does the new spur do.

 

[sparky1508]

Minor Works then, what does the new spur do.

It feeds a double socket in a small office to power a computer.