Advice on how to check mains tolerances

ShadowClaw

Hi Everyone,

Looking for some help on checking the mains in my house. Symptoms are lots of bulbs blowing (both LV on electronic transformers and normal incandescent ones) and also I have had a number of mains thermostats on my underfloor heating blow which have been quite expensive to replace.

The ESB put a data logger (black box: nothing to see on same) on the mains for around a week and I got a letter back stating that my system was within normal tolerances.

I have two questions:

1. What are the tolerances that the ESB guarantee to deliver to? I know its single phase and supposed to be 240V 50Hz. What criteria should I be looking at?

2. How can I measure these criteria myself and give the ESB a printout to prove that they need to address the issue? Can someone recommend a meter or data logger that will measure fluctuations and give a printout or transfer the data to a PC? Can I hire such a thing cheaply / where? I would be willing to buy a multi-functional meter that has other uses as well at a reasonable rate.

3. If it's not a problem with the supply what could it be? House is approx 2500 sq ft. An ELCB went faulty and had to replaced once because lots of devices were tripping it if that's any help. Also I reckon the mains might be quite dirty due to the number of electronic transformers in use on the halogen lights and I believe these have a reputation of being quite noisy. There is lots of crackle type background noise on the hi-fi which probably confirms this but I don't see it causing the problems I have?

I'm looking to get an upgrade to my plumbing (well try and get it working as it should after many years!). This will involve a lot of rework of thermostats and control systems. Don't want to put the investment in a lot of kit only to have it blown up because of bad mains.

Any help out there greatly appreciated.

steifanc

you would need something like this for measuring power quality

http://radionics.rs-online.com/web/search/searchBrowseAction.html?method=retrieveTfg&binCount=1&Nty=1&Ntx=mode%2bmatchallpartial&Ntk=I18NAll&Ne=4294957972&Nr=AND%28avl%3aie%2csearchDiscon_ie%3aN%29&N=4294956655&Ntt=power+analizer

i cant quite remember what range the esb deliver there supply i think its
+-10%

it is very unlikely that you have enough halogen lamps to cause "dirty" or reactive power . an electronic transformer should be very quite unless the voltage is low or there isn't a pure sine wave present .

the hifi could be picking up any kinda interference , a high pass filter would sort that .

is your house near any industry , are the similarity's in the times the lights blow ?

you would not of been the first person that i have talked to about problems like this and when Ive delved deeper into the problem 6/10 its a problem in the fuse board or field related. caused by someone not knowing what they were doing and making a balls of the wiring.
that not being the case , the other two areas i would look into are esb demand spikes . your earthing system may not be properly neutralized

ShadowClaw

Thanks for quick response Steifanc. 592 notes is a bit steep for me to spend on a meter! There is a Tesco beside me but I can't swear that the lights blowing are anything to do with them. The idea that a "balls" was made of the wiring sounds a lot more plausible. Had lots of problems originally when we moved in with mcbs etc. tripping. Sounds like a job for a proper sparks. Is there anything I could do to check I have a good earth? Do you know if one of these meters can be hired?

The other reason I think you may be right about the board is that my sister lives next door and she has no problems with her electrics.

How long would it take for a good sparks to check my board out. Just want to know what I am letting myself in for.

Cheers.

maxfresh

It could be a good idea to get your whole house wiring looked at, the suggested time between periodic inspections in domestic premises is 5-10 years any reci or ecssa registered sparks will do this for you.

steifanc

it may be a possibility , a small one mind you that the activity of the tescos , if they were aiding there peak demand with generators or running chp plant etc. that it could interfere with your supply .

there are lots of tests for your earthing system , what id be concerned with is what potential the conductor is at .
in the interest of not putting your self at harm you need to get a registered contractor and they will preform the tests for you.

ShadowClaw

Tnx maxfresh and steifanc. I will try and get a good sparks to give my system the once over. The house is 10 years old.

Just wondering if Tesco is doing something to cause problems can I put in something to isolate this or is it something the ESB should be doing?

Tnx again.

Oh Oh two more lv halogens just gone!

Stoner

RoundyMooney answered a similar question on this before, might be worth a PM leading him to this thread.

Davy

ShadowClaw wrote: »

The ESB put a data logger (black box: nothing to see on same) on the mains for around a week and I got a letter back stating that my system was within normal tolerances.

I have two questions:

1. What are the tolerances that the ESB guarantee to deliver to? I know its single phase and supposed to be 240V 50Hz. What criteria should I be looking at?

Between 207 - 253 volts @ 50Hz. The thing they fitted would have been a voltage recorder most likely and would tell them exactly what you supply was at. Did you get a graph with the letter? Might be worth asking for a copy, to see if your even close to the limits.

ShadowClaw

tnx stoner. will do.

ShadowClaw

Davy just got the "bland" everything is alright letter. That being said no harm in asking for the graph. Will try and see if they will give it to me.

Cheers

steifanc

Davy wrote: »

Between 207 - 253 volts @ 50Hz. The thing they fitted would have been a voltage recorder most likely and would tell them exactly what you supply was at. Did you get a graph with the letter? Might be worth asking for a copy, to see if your even close to the limits.

so the esb transmit between 207/253 in accordance with European Standard EN50160 , you would wonder what the etci go on about claiming 4% is the maxium they will except , so is that 4% of 230v or 4% of the transmission.
just in general intrest , ive had many rows/debates with the so called etci..

@shadowclaw ,what was going on when you had to have your elcb replaced ,? and was it a elcb or an rcb , do you know.? and when it trips is it just your sockets or is your whole board going dead . are you in a sandy area ?

ShadowClaw

Steifanc

I stand corrected. It was a rcd. Just the sockets tripped if memory serves me right. Bulbs had been blowing but the rcd had not tripped. It was when we put in a new washing machine that it tripped. Got washing machine replaced. Still tripped. Then noticed toaster was tripping it so got it replaced. No explanation from the sparks that did it except that it was "very unusual" for one to go.

Since then lots of bulbs gone but its the stats on the underfloor heating going thats really expensive. They are mains and not lv powered. Ufh actuator heads are switched by mains relays. I just thought that if I have mains problems that it is also frying my stats.

Not in a sandy area. Sticky clay area.

Thanks for any help.

RoundyMooney

Just saw this now; I'll give what advice I can.

If it were just recessed lights popping, I'd be thinking heat, but if normal pendants are going too, that rules out ambient conditions.

Actually I see you've lost a couple of stats as well

Anyway, starting with the ESB end, the voltage recorder will monitor both voltage and load, and provides a graph of same over a seven day period (actually 14, depending on the type), but they may not be left in that long.

What ESB look for include dips in supply at peak times, indicating a capacity issue, intermittent/regular dips (geothermal pumps, given their size, are notorious for this, in rural areas mostly ofc), and spikes as well.

I have to admit, that the minima are not very strict; basically a voltage tolerance from 207-253v (10%) conforming to EN50160 (a cenelec guideline dating from the 90s-a google will probably throw up a document with more details, it's heavy reading though),

However, this voltage tolerance is only itself guaranteed for, I think, 95% of the time.

Moving on from that, which isn't solving your problem, ESB as a rule have no facility for sending out the graph to you. I'd suggest putting in a call to your local area office, and asking to speak to the Customer Services Supervisor, and asking him if he would go through it with you, or if one of his staff could do so. No harm in asking anyway.

If this was a low voltage issue, I'd be thinking that you would be experiencing visible effects, machines taking longer to go through their cycle (most modern machines are timed, these days, which means that low voltage can cause them to finish their wash cycle with water still in, rare, but it does happen), and flickering lighting.

RCD's can and do go faulty, but it's suspect as well that one failed. It may be a red herring, but then again... Have you had any issue with the new one tripping at all?

Off the top of my head, I'd suspect harmonics or surges on the incoming supply, I can't imagine stray current flowing in the earth (or a dodgy neutral-the RVM-voltage recorder-would seem to rule that out as well!) being the cause. Did you say there was a Tesco nearby? Might be worth asking them if they generate on peak, but I can't imagine they'd be too forthcoming with that info, unless you know someone in there.

Can you nail this down to any time of day?

As well as talking to the local lads, I'd take some preventative action; have your sparks fit surge protection in your distribution board, these are not that expensive, and I can't understand why they aren't a regulatory requirement, with the cost of the kit we have in our homes these days. Ask him to double check the loop impedance while he's there

Come back and let us know how you get on as well.

ShadowClaw

Tnx a mil Roundy. The surge protector sounds a real proactive thing to do. I have a new sparks who I hope to line up.

No RCD issue since. Just blowing bulbs and stats.

Will ask him to perform all tests/advice as per here and will get back to you.

dont know about the ESB area supervisor. I really p£$"ed them off when I cut down a pole they would not remove when I put the supply underground. had to pay them a whack of money to pull a cable through the ducting I laid......maybe the guy has moved on.....will give it a bash....god loves a tryer

thanks to all for the help given. I now have something to try and aim for. Keep post open. I will get back to you all.

Cheers.