Power loss

[mechelec]

So Zs a lot lower than l-n impedance so that indicates a neutral fault doesn't it ! Again Check l- n on other circuits. You are looking for a high impedance connection somewhere internally. Do not leave until you have found it. If it causes a fire you will take an amount of responsibility.

 

[mechelec]

Test between l and n on the flex supplying boiler on ohm meter getting 130ohms

Just read the above again. Are you using loop tester or ohmmeter ????? If ohmmeter leave well alone and get some help in.

 

[NickD]

Was out on call last night and got this job.old lady says whenever her combi boiler fires up her lights dim,she loses picture on her tv and sometimes if she is in shower the shower will fail.i tried turning the boiler on at the stat but none of the above happened.the boiler has its own circuit and is supplied from 6a mcb.i checked at fuse board and the 25mm live incomin tail was a bit slack so tightened it up thinking that because the problem was affecting numerous circuits it was a supply fault.she has phoned in today again and says the same thing about the boiler firing up.any ideas?

You may have done this, but...safe isolate and thorough check inside CU, tugging looking for loose/broken conductor, inspect and tighten every screwed junction. Carefully tug tails upstream of CU looking for loose junction.

Combi boilers can cause RF (TV, radio etc.) interference when firing up which could explain the TV picture problem. Shower "failing" (in what way does it fail? is it a mixer shower taking hot water from the combi?) could be a boiler problem, poor combis can be pretty rubbish with the water temperature fading in/out. Which leaves the lights dimming issue. She says *whenever* the combi kicks in the lights dim but you say you haven't seen it so think you need to clarify. But the first two out of three (TV picture, shower "failing") could be nothing to do with the fixed wiring. Obviously it is your responsibility not mine to fix the fault and I take no responsibility for the veracity of the above comments and what you may or may not do with them is entirely under your own responsibility.

 

[ThrownRazor25]

I have checked litterally every socket,switch,light fitting I can get too.checked all the connections at the fuse board everything is sound.could it be a fault on supply side ie scottish power side?

its an electric shower Mira advance

 

[NickD]

Do the lights dim and stay dim while the combi is on, or briefly flicker dim? Is that a power shower or electric shower? How is the shower wired in and protected? If you turn the shower on does it make the combi fire up?

 

[ThrownRazor25]

No the lights dim then back to normal within seconds she loses the picture on her tv and if she is in shower it cuts out.its an electric shower not a mixer wired in 10mm to a pull switch fed from 40a mcb.No the combi does not fire up when the shower is turned on

 

[nickblake]

check the main switch if there is an intermittent fault it could be there get in DNO to check the cutout and supply

 

[Meggerman]

What is PSSC between Line of Main Switch and Neutral Bar?

 

[Badged01]

What day of the week does this occur the most on?

 

[ThrownRazor25]

Pfc is 2.1 and it happens every day randomly

 

[ian.settle1]

What day of the week does this occur the most on?

I was thinking more along the lines as to what time of day is it happening as if he goes during the day the problem may not show with people being at work but when everyone is home from work etc and they are cooking, showering etc then if it is a DNO fault it is more likely to show with the higher loading

 

[mechelec]

Phone DNO explain you are having volt drop issues and they will come do some checks. If they find nothing I would insist they fit a voltage and current recorder. Tell the client to note times and date when dips occur this can then be compared with DNO recorder trace. This will either point to external or internal fault.

 

[guest119]

Check continuity across the main switch (with an ohmeter) as sometimes they can get gritted up inside.

Boydy

 

[ed.db]

Is there a capacitor across the pump motor? It could be failing ? or leaking .
It does sound like a Neutral fault ? Check if current ( ammeter) on N and CPC
You could run a temp feed to boiler via a seperate dp RCBO from supply side of existing con unit see if problem still occurs?

 

[ed.db]

You could take a temp clean supply from a DP RCD /RCBO fed from incomer to Clients
Con unit to the spur at the boiler. See if the fault occurs?
Have you looked at the Capacitor on pump motor it could be leaking or failing?
It does sound like a Neutral fault though? Have you checked current on N+ CPC