Electric cooker feed SWA external

[bigspark17]

Why not run an swa external then come in under the plinths up into a cupbord gland into an appropriate isolator then hr flex into appliance?

 

[gazdkw82]

would it not be easier to just use one of the cores as a cpc from the CU to the cooker position?

Does the armouring have to be earthed? is it advisable to earth the armouring and then use a separate core for cpc?

 

[Pete999]

would it not be easier to just use one of the cores as a cpc from the CU to the cooker position?

Does the armouring have to be earthed? is it advisable to earth the armouring and then use a separate core for cpc?

If you intend using a separate core as the cpc you will still need to earth the armour at the CU end. I don't mean to be disrespectful, but the questions you ask makes me wonder if you should be doing this work at the stage you are at in your training.

 

[gazdkw82]

well iv installed SWA before so I'm comfortable with that. Iv always worked on the basis that the armouring should always be earthed and then use a seperste core for cpc.

However, I have read Somewhere recently that it's not advisable to do both but I suspect that in that situation someone was connecting the earth from the armouring together with the cpc

 

[Pete999]

well iv installed SWA before so I'm comfortable with that. Iv always worked on the basis that the armouring should always be earthed and then use a seperste core for cpc.

However, I have read Somewhere recently that it's not advisable to do both but I suspect that in that situation someone was connecting the earth from the armouring together with the cpc

I believe that the limit for using the Armour as a cpc is @95mm2, due to the size equivalent between steel and copper, I recall seeing a chart somewhere, it is possible to use the armour as the means of earthing, but you will need to ensure the glands at both ends are properly terminated, by that I mean cleaning the box you intend using as a junction or using proprietary earthing lock nuts.

 

[gazdkw82]

yes, and obviously the resistivity of copper/steel is different so using the armouring as cpc aswell as a copper conductor is not advisable

 

[telectrix]

yes, and obviously the resistivity of copper/steel is different so using the armouring as cpc aswell as a copper conductor is not advisable

nope.you can use both the armour and a core for cpc. only difference being that if you only earth the armour at the supply end, (to comply with earthing it), it won't be part of the cpc for the circuit.

 

[gazdkw82]

nope.you can use both the armour and a core for cpc. only difference being that if you only earth the armour at the supply end, (to comply with earthing it), it won't be part of the cpc for the circuit.

really? both connected together?

 

[Pete999]

really? both connected together?

Why not?

 

[telectrix]

yes, why not? they must be connected to earth the armour anyway. and as for building control. sod 'em on a minor job like this. never seen anyone prosecuted for failing to notify. it's only when someone gets hurt that the suits get off their shiny arses and make noises.

 

[gazdkw82]

it just doesn't seem right. I guess fault current will always just find the easiest path route to earth

 

[Bobster]

At the fault current you will be looking at, the armour and the internal CPC can most likely handle the fault current individually, so connecting them together is really no issue.

 

[Pete999]

At the fault current you will be looking at, the armour and the internal CPC can most likely handle the fault current individually, so connecting them together is really no issue.

Not got the idea yet? OP

 

[Ian1981]

Armour will be acceptable as a cpc in most cases

 

[gazdkw82]

I know armouring is ok as cpc on its own but I didn't know you could use both armouring and a core as a joint cpc