couple of questions

[soulman]

hi, couple of quick questions;

firstly gridswitches, can you use pvc surface mounted box, couldn't seem to get it to fit grid fram sits to far back?

secondly if a building has an overall 100ma rcd would using 30ma rcbo's in the db overcome the problem of the taking out the whole building under fault conditions in theory i think it should?

cheers

 

[Zeespark]

Grid switches yes you can, the grid frames are fitted first, then the front plate.

I am assuming that the fuseboard is TT and metal clad? If so, then I would use RCBO's rather than an RCD/MCB mix personally.

AndyGuinness

 

[soulman]

hi mate thats what i done but the grid frame sits to far back into the enclosure, the fuseboard is metalclad and is tns

 

[Zeespark]

Metalclad TNS? no need for the 100mA RCD at the front end then, just use a 100A main switch and RCBO's or RCD/MCB mix.

Can you not use a deeper box for the grid switches?

AndyGuinness

 

[soulman]

The 100ma rcd can not be touched its actually before the energy meter as part of the landlords supply. the surface mounted boxes the problem is not the depth as you screw back the grid plate it screws all the back into the enclosure its fine with a metal backbox or dryline box.

cheers

 

[Zeespark]

Then I dont know what suggestions I could make to answer your queries soulman, sorry.

AndyGuinness

 

[soulman]

cheers anyway andy.

 

[Zeespark]

No worries bud, I am just wondering why there is a 100mA RCD on the landlords supply side.

AndyGuinness

 

[Doc Hudson]

Is the 100ma a time delayed RCD? It would have to be time delayed to achieve any discrimination.

Doc H

 

[Evans Electric]

Using a grid switch with a surface pattress , you need to to leave the grid loose on it's screws , fit the plate and use the plate screws to pull the two together .

Trial and error, if plate is loose , wind the grid back slightly but not right back so that it sits on the fixing pillars.

Easier to do than describe TBH!!!

 

[soulman]

thanx mate figured it out tonight, cheers doc hudson