Tripping RCD advice

[bilbo_88]

Hi!

Need to pick some brains as I am truly stumped by this one

call out to a flat with nuisance tripping. On arrival tested circuits and all IR tests between LE were coming up relatively low, between 0.50-0.80 with the exception of ring main coming out as 0.01. There has recently been a leak from upstairs water tank so must be water somewhere, but at no outlet is there any sign of water (we checked lights, sockets, the lot) No sign of water in DB. Now the tenant told me not only was the RCD tripping but the main switch also. Now as far as I was aware these are isolator a only but low and behold whilst I was there I witnessed it trip, as well as the off peak board (was a late night call out).

For the sake of the tests, after removing the main fuse I also tested meter tails, showing up as 0.00 IR between LE but fuse won't blow and seems fine? Got my other fluke tester out as I was convinced my multimeter was going up the spout...same results.

Has anyone experienced anything like this? Either I'm not as good as I thought I was or the flat is haunted haha

any advice is massively appreciated!

thanks

 

[bilbo_88]

Worth mentioning installation is about 25 years old

 

[Darkwood]

When you were testing did you Isolate the Earths and Neutrals from the CU, if not did you test with the fuse out of final circuit but main switch on?

Don't forget the Earth is Strapped to Neutral at the DNO side if not a TT and you probably still have something in the circuit so you will get a very low L/E readout as it goes through the load, down the N to the E strap point hence your reading.

Remember the key points you were taught when doing IR tests or your reading won't mean jack.

 

[bilbo_88]

That would explain the tails, but for the circuits I had everything removed?

 

[Octopus]

Best you test each circuit for it individually. Only then will you make any progress. Forget this global if nonsense

 

[PEG]

^ Agree...music,news,vaccinations...all work great going global... looking for a specific fault,requires specific testing. Individual results can then be studied,to build a better picture of what is happening.

Also, it is not clear whether you have identified the "main switch",as an RCD or isolator. If it is the latter,and you have witnessed it "tripping"...then there are stranger forces at work :devilish:

 

[Farmelectrics]

Individual ir testing is we're you start let us no the outcome good luck

 

[bilbo_88]

Hi All
thanks for feedback. Tested all circuits individually and results of IR are as follows

MAIN SWITCH
Circuit 1 Water Heater LE 1.2Mohms LN >299mohms
Circuit 2 lights LN-E 3.45Mohms
Circuit 3 shower LE >299Mohms LN >200Mohms (this circuit for some reason was installed without RCD protection)
RCD 1 63A 30mA
Curcuit 4 cooker LE 1.79Mohms LN 1.99Mohms NE 2.30Mohms
circuit 5 ring main LE 0.65Mohms LN 0.66MOhms NE 0.66Mohms
circuit 6-8 all heater Spurs again IR of between 2-6Mohms

Again whilst I was there I watched the main isolator (Wylex not an RCD) 'trip'???

as well as this tenant claims same is happening with the off peak main switch as soon as it kicks in at night.

Whenever I text a circuit for a 2nd time I get fairly different results

The problems start at about 4 and go on until approximately 9.30 in the morning.

Wondered whether there could be potentially some form of thermal damage where cables enter board above ceiling or something.

Has anyone ever seen a Main Isolator do this before??? It is the RCD tripping also however

thanks in advance

 

[Pete999]

Circuit 3 thats because it's in a shower/bathroom I suspect
You watched the main switch not a RCD trip?????

 

[bilbo_88]

Circuit 3 thats because it's in a shower/bathroom I suspect

it DOESNT have RCD protection. Probably installed around 3 years ago. No certificates either.

 

[Pete999]

it DOESNT have RCD protection. Probably installed around 3 years ago. No certificates either.

Sorry mate read your post wrong, apologies

 

[Flanders]

Looks like its somthing to do with thd sockets could be a junction box under the floor full of water , is it posible to disconnect the socket circuit completly , adfor tns main switch triping is imposible unless the swich is warn and gravity to pulling it down which i have never seen or herd of

 

[bilbo_88]

I have always known this about main switches but on my heart I witnessed it! On both on and off peak boards?!?! I have never seen it before!

 

[plantpot]

Can you post a picture of said main switch to put our minds at rest

 

[bilbo_88]

Haven't got a picture of the actual one but it is this
http://m.NoLinkingToThis/p/wylex-10...d%20Lighting&gclid=CK3m4rH08soCFRSNGwoddRsPgw
i promise lol

 

[Pete999]

Haven't got a picture of the actual one but it is this
http://m.NoLinkingToThis/p/wylex-10...d%20Lighting&gclid=CK3m4rH08soCFRSNGwoddRsPgw
i promise lol

Have you changed the unit? could be it's a duff Isolator

 

[Octopus]

Hi All
thanks for feedback. Tested all circuits individually and results of IR are as follows

MAIN SWITCH
Circuit 1 Water Heater LE 1.2Mohms LN >299mohms
Circuit 2 lights LN-E 3.45Mohms
Circuit 3 shower LE >299Mohms LN >200Mohms (this circuit for some reason was installed without RCD protection)
RCD 1 63A 30mA
Curcuit 4 cooker LE 1.79Mohms LN 1.99Mohms NE 2.30Mohms
circuit 5 ring main LE 0.65Mohms LN 0.66MOhms NE 0.66Mohms
circuit 6-8 all heater Spurs again IR of between 2-6Mohms

Again whilst I was there I watched the main isolator (Wylex not an RCD) 'trip'???

as well as this tenant claims same is happening with the off peak main switch as soon as it kicks in at night.

Whenever I text a circuit for a 2nd time I get fairly different results

The problems start at about 4 and go on until approximately 9.30 in the morning.

Wondered whether there could be potentially some form of thermal damage where cables enter board above ceiling or something.

Has anyone ever seen a Main Isolator do this before??? It is the RCD tripping also however

thanks in advance

good update matey

best you change the isolator - I am surprised that it's tripping, And on the off peak board.

the 4am to 9.30am bit looks as if the off peak is on then - could you visit at 8.30 to see this first hand?

 

[bilbo_88]

Sorry mate meant to say 4pm until morning. I will probably change both main isolators as a precaution. Have witnessed both main isolators 'trip' and the RCD when I was there Tuesday night about 10pm. So strange

 

[Octopus]

Sorry mate meant to say 4pm until morning. I will probably change both main isolators as a precaution. Have witnessed both main isolators 'trip' and the RCD when I was there Tuesday night about 10pm. So strange

Now that is VERY odd. Are you sure that they are not 100mA RCD's?

 

[bilbo_88]

Just got customer to email pictures for all you non believers lol
though it is a Wylex in an old MEM board however off peak is MEM main switch