RCD trips out

[jaez]

I our house the RCD trips out about 3 times a week at approx 5pm. The trip can be reset straight away. The MCBs don't trip at all

This even happens when we are away and all plugs are pulled out.

We having nothing that comes on or goes off timed at 5pm so can it be caused by neighbours equipment or mains spikes

What is the best way to try to prevent it happening in future

 

[DESL]

Does it trip at the same time or is it the time you get home and discover it?

If it trips at a regular time is it boiler?

Or is there something that you switch on?

 

[jaez]

It only ever trips out at about 5pm

We have unplugged everything possible and it still does it

The gas boiler hot water timer is set to 4am and 7pm and the house heating is on all day but with different temperatures at different times and none of these is 5pm! If it were the boiler then would it not do it at other times too

How can we test to see what happens at 5pm?

 

[DESL]

If it were the boiler then would it not do it at other times too

If the fault was with the heating RCD would trip when boiler fires up from cold

At least you can follow a process of elimination if RCD trips at the same time every day.

So isolate each cct in turn at 455pm each day and see if RCD trips a 5pm.

 

[JohnD]

do you live in town or country

do you have an overhead or underground power supply

do you live in a flat, terrace, detached house

what time do your neighbours come home (up to 3 doors away each side)

are you close to a light industrial unit or someone who does car repairs or similar

do you have outbuildings, external lighting, garden fountains or sockets

how old is the house

how old is the electrical installation

what brand is the consumer unit

what circuits are controlled by the RCD, and what circuits aren't

have you seen traces of rodents in your house

what pets do you have

is there a water tank in the loft, and have you looked up there for water leaks or gnawed cables

do you have a cellar

do you have a solid (concrete) ground floor or timber

when did this start happening

can you post a photo showing your incoming electricity cable, the service head and suppliers fuse; the main earth and other Green & Yellow cables, the meter, your consumer unit, and the cables between them. this will give us some clues about your installation.

 

[Richard C]

Had a very similar problem except tripping occurred at around 03:00 so at least you’re not poking around in the middle of the night! After a week of messing around pulling out plugs, trial & error elimination tests & going through various local farm/industrial unit/neighbour’s supply theories, I was still no nearer locating the fault &, following advice of this forum, finally managed to borrow some test equipment. Within 15 minutes the RCD had tested out OK & I managed to locate an earth/neutral fault on the downstairs lighting circuit. A further ½ day was spent ripping up floorboards & tracing the fault back through said circuit where it finally turned out to be a tiny nick in the neutral cable going down to earth which had not surfaced during the new C/U commissioning tests or caused any problems for the first 6 months the unit had been in use.

Best possible explanation for only tripping in middle of the night was that the local sub-station was putting out a higher voltage at that time due to low demand which was enough to put the RCD outside trip tolerance; good luck tracing the fault, I would never have located it had I not been able to borrow suitable test kit!

 

[Steve3948]

If it were the boiler then would it not do it at other times too

If the fault was with the heating RCD would trip when boiler fires up from cold

At least you can follow a process of elimination if RCD trips at the same time every day.

So isolate each cct in turn at 455pm each day and see if RCD trips a 5pm.

Isolate Live, Neutral and earth within fuseboard of each circuit, one circuit at a time until you can be sure which circuit is responsible.
This will narrow it down.

 

[JohnD]

Does he have the knowledge and confidence to do that safely, Steve3948?

 

[securespark]

Rich C - does that mean you've had a new CU with RCD protection to the lighting, or have you got a TT supply?

 

[Steve3948]

Does he have the knowledge and confidence to do that safely, Steve3948?

Only he will know that, if he is unsure then he should leave it to the pro's

 

[JohnD]

We've seen no further info or responses since breakfast time

 

[Richard C]

Rich C - does that mean you've had a new CU with RCD protection to the lighting, or have you got a TT supply?

Yes, new C/U has one RCD for all circuits & it is on a TT supply.

 

[JohnD]

Why is Richard C's problem creeping onto jaez's thread?

 

[Richard C]

Why is Richard C's problem creeping onto jaez's thread?

I don't have a problem any more; my original post could be relevant to the OP’s problem & I was just answering the question!

 

[jaez]

o you live in town or country = Suburbs of Colchester

do you have an overhead or underground power supply = underground

do you live in a flat, terrace, detached house =detached chalet bungalow

what time do your neighbours come home (up to 3 doors away each side)= there most of the day

are you close to a light industrial unit or someone who does car repairs or similar = no

do you have outbuildings, external lighting, garden fountains or sockets
= 1 garden socket with rcd as it comes into house

how old is the house = 1953ish with major revamp & rewire in mid 1990's

how old is the electrical installation mid= 1990's

what brand is the consumer unit =MEM

what circuits are controlled by the RCD, and what circuits aren't
= all power is - all lights not

have you seen traces of rodents in your house = no


what pets do you have = none

is there a water tank in the loft, and have you looked up there for water leaks or gnawed cables = yes - no leaks - not sure about cables

do you have a cellar = no

do you have a solid (concrete) ground floor or timber = solid wood floor on concrete - no cables under


when did this start happening =May but slowly getting worse over time


can you post a photo showing your incoming electricity cable, the service head and suppliers fuse; the main earth and other Green & Yellow cables, the meter, your consumer unit, and the cables between them. this will give us some clues about your installation = will try to do this soon


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