Tripping RCD

[lofty84]

One of the RCDs keeps tripping in one of the propertys we are working on. The RCD supports the ring in the kitchen, lights and doorbell from what I can remember. when we put the ring on the other rcd in the consumer unit it didnt trip, but we need to investigate this tommorow. Any ideas whats happening. I know the purpose of a rcd is to monitor the circuits it is protecting and turn its self of if it notices a difference in current going out on the line and back on the neautral of 30mA or more.

 

[telectrix]

Of the top of me bonce, assuming a newly installed circuit.

Visual checks (usually done during construction if working alone).
End to end continuity of conductors, using either R1+R2 method or wandering lead method (favour the first as you'll get polarity as a side effect).
Insulation resistance testing of conductors for final circuits
Polarity checks.

Then on to live testing:
Live Polarity Test.
Ze, current tests, Zs.
Then on to RCD/RCBO tests
and finally functional testing.

In practice for an existing installation you'd normally check Ze, PSSC etc

you missed out the wet finger test! :crazy:

 

[topquark]

you missed out the wet finger test! :crazy:

Damn, knew I'd miss something ... ah don't forget bondage ()conductors when doing continuity.

 

[topquark]

Sorry, what's Safe Isolation again, remind me

 

[lofty84]

doe anyone want to expain it for a simpleton. Ie go into cosumer unit and put in a temporary link between the circuit ur testing and the earth bar. get ur meter and put it on low ohm resistance setting. null leads. test between line line and cpc at each point on that circuit.

ps. as its a dead test does that mean i can get away with just tripping the main switch, or will i be best of fully isolateing things and tracking down the source which feed the consumer unit and turning that of... I think i would sooner do this but if its not necesary (sp)?

 

[topquark]

Get yourself of copy of Guidance Note 3: read and inwardly digest it's contents until you can recite it in your sleep.

 

[topquark]

Sintra (one of the moderators) has posted a guide to basic testing here: http://www.electriciansforums.net/i...allations/16621-basic-testing-procedures.html

 

[GLENNSPARK]

doe anyone want to expain it for a simpleton. Ie go into cosumer unit and put in a temporary link between the circuit ur testing and the earth bar. get ur meter and put it on low ohm resistance setting. null leads. test between line line and cpc at each point on that circuit.

ps. as its a dead test does that mean i can get away with just tripping the main switch, or will i be best of fully isolateing things and tracking down the source which feed the consumer unit and turning that of... I think i would sooner do this but if its not necesary (sp)?

Trust me....and do as TQ suggests mate as if you want to get into inspecting and testing then GN3 is the way forward....

 

[robsparky1975]

Hi lofty84,im a bit worried as you have described yourself as a simpleton!!!!!!!!,now for reasons of safety if you feel that you are not competent to do testing then maybe consult your supervisor,you may be joking about your competence or then again you may be a fully qualified but alarm bells are ringing.Im getting the fact that things were just switched on before testing,the old bang/no bang method,am i missing something lol

 

[telectrix]

I think his firm might be corner cutting. you can't blame the crew when the captain's wrong.

 

[BlueToBits]

From post #4

...
I forgot to mention it seemed to trip once the fridge was pugged in and opened

It's a bit of a long shot, but BBC Watchdog did a feature the other night on a commonly occurring fridge fault when opening the door of a Hotpoint Quadro. This could cause an RCD to trip.
BBC - Watchdog: Hotpoint Quadrio: Opening with a bang

 

[SimpleSimon]

Just to let you know gents, problem solved.
Neutral from new kitchen ring was into the wrong neutral bar.

Sent from my GT-I9100 using Tapatalk

 

[Peter Stanley]

you need to break down the circuits carry out a insulation resistance test
between live/neutral, live/earth and neutral/earth