Recording RCD readings

[s1m0n]

Hi,

When you have an RCD covering lets say 5 circuits, on the schedule of test results would you:

Do 1st line as RCD ,and then list the 5 circuits below that
but only put the RCD readings on the RCD line and leave circuits RCD readings blank.
or would you put the same reading for each circuit.

(We were taught just to take one reading as the RCD is common to the other circuits)

hope that is clear.

for an added twist, one ciruit is a lighting circuit with no CPC, that would be a N/A for RCD readings ?

Thanks In Advance

 

[Spa Key]

Hi,

When you have an RCD covering lets say 5 circuits, on the schedule of test results would you:

Do 1st line as RCD ,and then list the 5 circuits below that
but only put the RCD readings on the RCD line and leave circuits RCD readings blank.
or would you put the same reading for each circuit.

(We were taught just to take one reading as the RCD is common to the other circuits)

hope that is clear.

for an added twist, one ciruit is a lighting circuit with no CPC, that would be a N/A for RCD readings ?

Thanks In Advance

Leave them blank or put a line across the box.

As for the no CPC, why would it be N/A for the RCD? It's still protecting the circuit.

 

[JUD]

This is how I do it

Just put the RCD readings on RCD line as you say

 

[s1m0n]

Hi

Thanks for that

I was just wondering about the lighting circuit with no CPC,
there would'nt be an earth path back to operate the RCD,

I am I understand this correctly or just making it complicated

Thanks

Simon

 

[JulianC]

RCD monitors current in L & N and trips when it detects an imbalance between the two. Earth is irrelevant.

 

[s1m0n]

Thank you,

I get blinked sometimes when looking too deeply,

I had a certificate not accepted as I only put in the results on the RCD line of the schedule of test results. not for each circuit protected by it,

I put N/A against the circuits,
we were taught at collegeto do that instead of a line.

so I think I added to the problem,

Thanks again
Simon

 

[JUD]

RCD monitors current in L & N and trips when it detects an imbalance between the two. Earth is irrelevant.

I would hardly say earth is irrelevant.

As you say the RCD monitors the Line & Neutral current and detects earth leakage/faults which is what causes the imbalance.

 

[JulianC]

I would hardly say earth is irrelevant.

I would as far as the RCD is concerned. It doesn't care where the leakage is, it just acts on the imbalance. But yes, presence or not of a cpc in a lighting circuit will determine whether or not the trip will occur when a dodgy live connection touches an earthed metal fitting for example, or whether or not the fitting just sits there at line potential until you come along and touch it. Earth is of course very relevant in that case

I was just trying to clarify the point that an RCD does not trip by measuring the leakage current down an earth wire. There have been on or two posts on here lately, under this wrong impression. And I am on a crusade

 

[Des 56]

The way I would put it.is that, an rcd operates when there is an imbalance greater than its operating level of leakage,based on its rating

When that imbalance becomes greater, for whatever reason, then it will operate

The imbalance can be created by current being conducted to earth through a cpc or a person

An earth is not required.but a path to earth is required
Simples

 

[JUD]

I was just trying to clarify the point that an RCD does not trip by measuring the leakage current down an earth wire. There have been on or two posts on here lately, under this wrong impression. And I am on a crusade

Earth is irrelevant.

So what you meant to say was the earth wire is irrelevent