Reference method

[Dave 85]

What reference method would you guys put for standard house wiring (T&E through loft/underfloor/chased in walls behind capping)

 

[Plonker 3]

Worse case scenario on the cable run.

 

[telectrix]

debateable between method c and method b.

 

[Dave 85]

Cheers guys, another quick one: When you put the R1+R2 reading for an RFC on the cert, do you put the reading obtained with the R1 and R2 cross connected or just bridge between R1 and R2 at the furthest point and take the reading at the C/U (surely this reading would give you the true earth fault resistance). I understand how to do RFC testing just never been 100% as to which result I record.

 

[telectrix]

on a |RFC all the R1+R2 readingds will be the same whatever socket you measure at. simply because of the cross connection at the |CU. (not allowing for spurs)

 

[sjm]

What reference method would you guys put for standard house wiring (T&E through loft/underfloor/chased in walls behind capping)

If the cable is under insulation in the loft then 100 or 101 depending on depth of insulation.

 

[Guitarist]

Cheers guys, another quick one: When you put the R1+R2 reading for an RFC on the cert, do you put the reading obtained with the R1 and R2 cross connected or just bridge between R1 and R2 at the furthest point and take the reading at the C/U (surely this reading would give you the true earth fault resistance). I understand how to do RFC testing just never been 100% as to which result I record.

On an RFC it will be the cross-connected reading which will give you the true reading due to resistances in parallel, ie. (r1+r2)/4
On a radial it will be linked R1+R2

 

[JUD]

What reference method would you guys put for standard house wiring (T&E through loft/underfloor/chased in walls behind capping)

As others say, if you have more than one install method along a circuit always go with the one with the lowest current-carrying-capacity for the cable you're using.

 

[Guitarist]

C'mon Dave. We answered your questions. A quick acknowledgement wouldn't go amiss here mate....

 

[Dave 85]

I did say "cheers guys" to the first answers but here it is again...
cheers guys
Still wondering though...
What would you guys usually put on the cert of a standard domestic property as reference method, B or C? I find the descriptions in the regs a bit ambiguos

 

[Des 56]

A kitchen or downstairs ring would be under the floor boards and down the walls,so ref method C,likewise a cooker circuit
An upstairs lighting circuit would be through the insulation so the 100s club would be more likely,likewise a shower cable
If its a beautiful surface trunking or conduit job,ref B,capping over the cable,still C

 

[Dave 85]

Cheers Des, very helpful
Forgive my ignorance but what is the 100's club? Is it like club 18-30 but for (very old) pensioners?
The first half of the above question is serious btw

 

[Des 56]

Dave The 100s club is a specific section for twin+earth cable in thermal insulation
100 101 102 103
If you meant the other part of my answer,thats a secret only us war babies know about :blush5:

 

[Richard Burns]

The "100s club" refers to the reference methods for T&E cable covered in insulation 100, 101, 102, 103: thin insulation, thick insulation, in insulated stud wall, in insulated stud wall not touching the inner edge.

Far too slow!!

 

[Guitarist]

I did say "cheers guys" to the first answers but here it is again...
cheers guys
Still wondering though...
What would you guys usually put on the cert of a standard domestic property as reference method, B or C? I find the descriptions in the regs a bit ambiguos

No problem Dave. I was referring to the RFC question, which you seemed a little confused about. Just wanted to make sure you understood what I had said, as you hadn't responded