17th edition Split board issues.

[SafetyFirst]

Hi guys n gals, i've fitted another general electric 17th edition split board. It's the 3rd one i've fitted and the 3rd one that i've had problems with.
Haven't changed many boards over, only ever done so for friends or family who've needed/wanted too, i still have my rewireble box taking care of things in my bungalow without any probs

The first board change i did after much head scratching i found a borrowed neutral with the lighting from down/upstairs after grouping lighting circuits onto one RCD. Also the two way switch was dodgy, all fixed and no problems reported six months down the line-all good.

Second board change, everything worked bar upstairs lighting, megga tested and found a very low reading between E-N so needed further investigating. Haven't had the time to sort that one yet but there's no rush as buildings going to be redundant for sometime yet.

Both jobs for my sis and bro in law.

Moving onto todays, for a friend of mine, currently living there. Moved in just before christmas, have changed all the lights over to new shiney one's. Changed all light switches to chrome and awaiting to do the same with all sockets.

Anyways the building is fairly modern, built in '98, old hrc fuses with 2 30A MCB's protected by a 30mA RCD. They served a ring for upstairs/downstairs general bedroom/living room sockets.
The other ring serves kitchen/utility/garage sockets.

The way i setup new 17th edition board was to split the rings onto either RCD's and what this results in is having just upstairs lights and kitchen sockets on one RCD that trips when powered. The other RCD (1) has downstairs lights/smoke detectors/genereal sockets/cooker (only oven 10Amps)/water heater (13Amp). Doesn't trip and all working fine.

After much head tearing the RCD (2) doesn't like the kitchen ring or the upstairs lights individually.

Have used old boards copper to create a temporary by-pass for the two circuits that are not liked by the RCD till i have time next weekend to megga those cables and further investigate this problem. Whats baffling me is the fact there wasn't a problem with the old RCD protecting the kitchen ring.

Imbalance issue?

What a mare eh!

These fully loaded RCD boards can be a blessing in disguise as there has to be a few issues with the wiring on the kitchen ring and upstairs lights. I just wish i could have one that goes straight forward for once!!

 

[Octopus]

Cheers Dan, like i say those are the point's i want to concentrate on, there's 3 lights outside the back garden, they even have their own trunking run, will give it a gander tomorrow. How will i know if those detectors are fried now?

Try the test button and see what happens!

 

[SafetyFirst]

Try the test button and see what happens!

Do i really want too though......how much are decent smoke detectors these days? Tenner each? Recommendations please.

 

[Des 56]

Buy a can of smoke
Read my own post and it sounds sarcastic

Buy a can of smoke alarm test spray for the suspect alarms

 

[Octopus]

Aico every time. Not the cheapest but the easiest to install and very reliable in my experience

 

[SafetyFirst]

Aico every time. Not the cheapest but the easiest to install and very reliable in my experience

Thanks Murdoch!

 

[Knobhead]

So you reckon the detectors will have had it then?

I’ve a confession to make here.

Years ago I wasn’t happy with some smoke detectors fitted in an office block (neither was anyone else, nearly everyone in the offices smoked then).

I tested them at 1000V. No trouble after that. Lighting circuit was OK, but RIP the smokes. They never did get replaced, one was in my office so I had a bit of a vested interest!

 

[trev]

I'm guessing you smoke tabs Tony

 

[SafetyFirst]

Well i did test them at 250v.......i'll soon find out tomorrow.

 

[Knobhead]

The works engineer was holding the stepladders while I did the test, he smoked Capstan Full Strengh!

 

[1shortcircuit]

You should be fine on 250v. I always run a 250 first just incase there is something that you have not been informed of or something you have missed. Just the other day I missed a neon on the cooker radial somehow but on another instance there was an additional floor to a property that I was not informed about lol Access was behind what looked like an airing cupboard door lol

 

[SafetyFirst]

Smoke detectors were both intact ok. Ran IR tests on cct with heads dropped out and gave me healthy reading. Re-installed and tested both working ok with interconnections making other beep in fault mode as norm.

However they've never been changed since original install and both need replacing as they're past their sell by date of 2005!
So next saturday i will fit 2 new smokes and a new light fitting for the on suite.

Still haven't located the fault on the upstairs lights. The outside lights are fed via the downstairs lights so its nowt to do with them.

I've been in the loft today, all chipboarded out apart from above the bathroom were they've wired spots. Took JB off to try and bell neutrals to earth out, this JB must serve most lights as the cables fork off like a spider. When i split neutrals i managed to find two seperate neutrals are shorting to earth. They both go in seperate directions from different lights.

It's confused me even more. Tried taking lights down but much easier with a second pair of hands so the owner (my mate) is gonna give us a hand next saturday.

Whats more confusing is that i re-tested the cct's IR, compared to yesterdays i got much healthier results of L-E 900 meg and N-E of 800+ so why when i bell earth to neutral out on continuity i'm getting a short? Maybe my multifunction tester needs calibrating.

Mind you i dismantled a dodgy looking fitting in the on suite yesterday but that wasn't the main problem.

 

[ringer]

Where you 'split the neutrals' I assume you mean that you disconnected different cables from the JB and tested them individually. Did these cables actually run to individual lights, or were they actually the supply (lighting ring = two cables) from the CU? If the latter, then that will explain why you are getting N-E short (assuming TNCS supply) unless you have disconnected cables (both N and E) for that circuit at the CU.

 

[Des 56]

Smoke detectors were both intact ok. Ran IR tests on cct with heads dropped out and gave me healthy reading. Re-installed and tested both working ok with interconnections making other beep in fault mode as norm.

However they've never been changed since original install and both need replacing as they're past their sell by date of 2005!
So next saturday i will fit 2 new smokes and a new light fitting for the on suite.

Still haven't located the fault on the upstairs lights. The outside lights are fed via the downstairs lights so its nowt to do with them.

I've been in the loft today, all chipboarded out apart from above the bathroom were they've wired spots. Took JB off to try and bell neutrals to earth out, this JB must serve most lights as the cables fork off like a spider. When i split neutrals i managed to find two seperate neutrals are shorting to earth. They both go in seperate directions from different lights.

It's confused me even more. Tried taking lights down but much easier with a second pair of hands so the owner (my mate) is gonna give us a hand next saturday.

Whats more confusing is that i re-tested the cct's IR, compared to yesterdays i got much healthier results of L-E 900 meg and N-E of 800+ so why when i bell earth to neutral out on continuity i'm getting a short? Maybe my multifunction tester needs calibrating.

Mind you i dismantled a dodgy looking fitting in the on suite yesterday but that wasn't the main problem.

Are you carrying out this testing at the same position with connections left as is ?

Are you perhaps splitting this lighting circuit with the circuit isolated and insulation resistance testing ( high megohm reading)at that point, then perhaps you are leaving the lighting circuit off ,then switching on the main isolator, then doing continuity of neutral - earth ( low ohms reading via earth - neutral link) ?

You seem to have anomalies with the testing procedure by obtaining these results,a quick flick of the testing leads to verify the function on both scales is but a moment to carry out,it can become a good habbit that is carried out continually before and during use of the instrument/s

 

[SafetyFirst]

Cracked it guys!

Renewed a T&E that had not one but two nails through it under the chipboard!

Full house 17th ed RCD protected!

Thanks all for your input.

Just gotta change all socket fronts to chrome and jobs finished........would have been quicker rewiring.

I've learnt one thing for any upcoming jobs, to take my multi function tester and give wiring a 250Volt megga test.

 

[SafetyFirst]

Also renewed old smoke detectors, bought Aico, they were £35 inc vat for two.

Also got new IP rated light fitting for en suite.

It'll be boxed soon and i'll be very glad when it is!lol.