Search results

Hi, could anyone explain why in a TT system, if the consumer unit has Single Pole RCBO's that it's also necessary to fit a 100ma TD RCD as a main incomer. Sorry but I can't get my head around this one! Thanks

Thanks alot for all your replies and suggestions. I've been back today and found some other stuff plugged in that I missed first time round. I've IR tested ALL the circuits and they're all around 299Mohm. As some of you suggested I think the problem is that one RCD is not sufficient for the...

Thanks Comms. I'm going back there today to take another look so will double check everything!

Thanks RF lighting. I tested L&N>E just in case i HAD left something plugged in - it's a very big house with more sockets than screwfix and I didn't fancy sending 500v up the plasma! I appreciate what you say about testing every circuit but it's strange that it only trips when BOTH ring...

Hi Sparkyspike The results on one ring were 48mohm (low but not low enough to trip an rcd?) The other ring was 150Mohm Thanks

Thanks for the replies, in answer to your questions: The RCD is a 80a 30ma - I swapped it with a new just to double check but still had the same problem. Pretty sure I unplugged everything. It's a TT supply I did the IR test between L&N (connected) and Earth (just in case something...

Hi, been to a house today and customer complains that the RCD trips SOMETIMES when she uses the iron and almost always when she uses the hob. The RCD will not reset unless all the breakers are first switched off. Apparently it's been like this for some years. Looks like the place was rewired...

Thanks for the replies. Yes, I know it passes but I was just curious as to why the 2 that I tried were both slower first time round. Thanks again.

No, I left the circuit connected. Ze was 0.21. Thanks

Hi, just installed a new CU for someone. ELI, IR, ZS etc for every circuit are fine. They only have one ring for the whole house and I've protected this with a 30ma RCBO. The 2 lighting circuits and cooker circuit are also protected by RCBO's. When I check the RCBO for the ring circuit it's...

Brilliant, thank you.

Thanks for the replies; main fuse is 100A so will use an 80amp fuse as suggested - and will site it next to the cutout NOT the CU as my first post says! (been a bit brain dead today, must be the heat) As I've not used a switched fuse before is there any particular make that you'd recommend to...

Hi, I've been to look at a job today (wiring an extension bedroom) and noticed that the meter tails are 10metres (yes 10!) long. Local DNO will only allow max of 5metres. Not been in the trade long and so not come across this problem before but was planning to install a 100a switch fuse next to...

Thanks. Sorry to sound thick but are you saying that you shouldn't test an RCD from a socket outlet but just at the board? :?

Thank. The leakage that RF talks about, is that more likely to be leakage from an appliance or from somwhere in the installation itself?

Thanks alot, will swap it and see what happens. Just out of interest COULD there be another reason? I've not come across one that fails on half test before :? Thanks

Thanks for the quick replies. Yes, I tested it in isolation, it failed the first time and then passed the second time I tried. Sorry, should have mentioned, I did a ramp test it came out at 15ma on one cycle and 19ma on another. Thanks

Hi, what would be the possible causes of an RCD failing the "half" test? Tested a 30ma RCD today after installing a new wylex split load board. It trips at 24ms on 1X test; 8ms on 5x test but fails the half test. There are 3 rings and 4 lighting circuits on the CU, I tested the RCD on each...

Thanks RFLighting. So I DID misinterpret the regs! I assumed (wrongly) that it was my responsibility to ensure that the circuit was future proof in the event that someone would change the fittings, hence my concern to get it right. Thanks a lot.

Thanks for the replies. Yes, I used 100w as per the OSG. I know it's highly unlikely that anyone will ever change the downlights for 35 100w tungsten lamps(!) but I thought I should do it by the book. CFL's is a good idea especially considering the cost of running halogens; but wouldn't I...