RCD

[RobinEL]

Hi,

I have a kettle that trip the RCD when plugged in to a RING cct, but NOT when plugged into a Radial cct.

The Ring cct is a new installation.

Is a ring more 'sensitive@ to leakage than a radial?

 

[PrenticeBoyofDerry]

Does the radial circuit have RCD protection?
If it does is it on the same RCD?
It could be that the earth leakage on one RCD is large enough to trip than the other.
It's likely the heating element in th kettle is starting to leak to earth.

 

[RobinEL]

Hi,

There is only one RCD.

It only trips if using the 'new' ring cct.

 

[PrenticeBoyofDerry]

Is the radial circuit protected by the RCD?
Most boards with a single RCD, often have circuits that are not RCD protected.
So press the test button on the RCD and see if the radial circuit has power loss.

 

[RobinEL]

Its is a single RCD covering all MCB's

The ring cct is new.

The kettle only trips the RCD if on the Ring cct.

Thanks

 

[PrenticeBoyofDerry]

Try another appliance at the same socket on RFC where kettle was plugged in to.

 

[JohnW2]

Its is a single RCD covering all MCB's. The ring cct is new. The kettle only trips the RCD if on the Ring cct.

It's difficult to make sense of that, unless the ring circuit has been wired incorrectly (e.g. neutral current not going through RCD) - but in that case the RCD ought to trip if anything is plugged into the ring circuit - do I take it that such is not the case?

Kind Regards, John

 

[RobinEL]

Hi,

Its is a NEW ring cct.

Other appliances DO NOT trip the RCD.

But a NEW Oven, run from a spur from the RFC does also trip the RCD.

Thanks
Robin

 

[PrenticeBoyofDerry]

Do you have the test results for the new circuit at hand?

 

[JohnW2]

Its is a NEW ring cct.

Was this new circuit properly tested - were RCD tests done from the new circuit?

I... Other appliances DO NOT trip the RCD.

I presume you mean they don't trip the RCD even if plugged into the same socket on the RFC which results in a trip when the kettle is connected?

But a NEW Oven, run from a spur from the RFC does also trip the RCD.

Perhaps not an ideal arrangement, but interesting, and confusing.

Do kettle and oven both result in trips every time they are switched on?

Kind Regards, John

 

[RobinEL]

NO

But the Electrician is returning next week.

Could the new RFC be incorrectly wired?

 

[PrenticeBoyofDerry]

I would suggest a ramp test on the RCD.

 

[JohnW2]

NO ... But the Electrician is returning next week. ... Could the new RFC be incorrectly wired?

As I said before, YES - but the most obvious wiring error would mean that anything plugged into the RFC (and switched on!) would cause the RCD to trip - and I think you're saying that is not the case.

The new circuit, and the RCD, certainly need to be properly tested (as they should have been when the new circuit was installed).

Kind Regards, John

 

[Taylortwocities]

It does sound like a traditional earth/neutral fault that will trip the RCD when a larger load is employed.

Usual culprit is the neutral of the RFC in the wrong neutral busbar in the CU, but not likely if there is only one RCD (as the incomer?).

If so, that leads us on to a fault in the ring itself. As asked above, the dead tests on teh circuyit prior to energisation should show this up.

RESULTS OF TESTS PLEASE!!

 

[JohnW2]

It does sound like a traditional earth/neutral fault that will trip the RCD when a larger load is employed. ... Usual culprit is the neutral of the RFC in the wrong neutral busbar in the CU, but not likely if there is only one RCD (as the incomer?). ... If so, that leads us on to a fault in the ring itself.

Indeed - but if the ring is wired correctly (e.g. neutral going to right place), the single RCD really should be oblivious to which final circuit a load is connected to - i.e. plugging the kettle into the 'radial' should 'look to the RCD' exactly the same as plugging in into the RFC (or any other final circuit) - yet one apparently trips the RCD and the other doesn't. For that reason, I think my money would probably be on something wring with the wiring of the ring.

Although I've asked a couple of times, I've yet to get an absolutely explicit answer as to whether it's possible for the OP to put any load on the RFC without tripping the RCD - if not, then 'neutral going to the wrong place' would clearly be high up the list of suspicions!

Some basic testing ought to elucidate the problem!

Kind Regards, John