Discuss rcd fault in the Periodic Inspection Reporting & Certification area at ElectriciansForums.net

Welcome to ElectriciansForums.net - The American Electrical Advice Forum
Head straight to the main forums to chat by click here:   American Electrical Advice Forum

Mike,

Im not sure I understand your question, may need more information.

As far as I'm aware, RCDs do not have to trip within 40ms @ 100% test. I was always had the understanding that the trips are;
No trip @ 50% or 1/2 rated
<200ms @100% or 1 x rated
<40ms @500% or 5 x rated

But, I was once told that RCDs can be slow in cold weather - it may be a myth, or someone taking the pi**.
 
Last edited by a moderator:
Yes Jules your right the 40ms is for 5x Rating

1x rating should trip in <200 ms for BS 4293
1x rating should trip in <300 fms for BS EN61008 or BS EN61009

michufc - onsite guide P91-92
 
hi in your experience what would cause a rcd not to trip in 0.4s at 1 x test

cheers mike

Sometimes depends on how old RCD is.

if its a few years then it has been known in the past that some can 'stick' if the test button hasnt been used enough.

This is the reason why they have them.

Alternatively it could be just faulty, new or old.
 
If its new and you have run tests on it and the test results do not meet the requirements then you may have a faulty switch?

It does happen and usually gets us running around like headless chickens trying to fault find.

You haven't said what brand it is but you would be surprised with some of the brands that have had to recall. Thats without the counterfit stuff that floats around.
 
Hi.

At th'end o't day if your not sure and think it may be faulty also, for your own peace of mind change the RCD.

But like the lads have said 1x does not need to disconnect in under 0.4s.

Cheers:D.
 
I've wondered about this: the device must disconnect in under 0.4 seconds, often put as 40ms. Thing is, 40 milliseconds is 0.04 seconds, so surely it should be in under 400ms not 40ms?

Where have I gone wrong?
 
hi in your experience what would cause a rcd not to trip in 0.4s at 1 x test

cheers mike


Hi there

could your rcd be on the supply side and not the load side ?

I tried to test a 30ma rcd ( before consumer unit) on a portacabin and whatever tester we used it would not trip it had been installed with incoming at the bottom of the rcd we tested at the top going out to the distboard but it all just was enclosed in the fabric of the building..functional still worked though

so it is possible to test on the supply side and think the rcd is shot. or sticking while the function works :)

cheers
 

Reply to rcd fault in the Periodic Inspection Reporting & Certification area at ElectriciansForums.net

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc

YOUR Unread Posts

This website was designed, optimised and is hosted by Untold Media. Operating under the name Untold Media since 2001.
Back
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock