Problems with Strip Light and low supply

[Mr Smyth]

Hi,
I am a Scout Leader and we are having some problems with a double strip light at the HQ. The light had started to flicker on start up but would eventually light up. This got worse and now it just flickers on and off. The problem is both tubes. We started by swapping starters but no luck so then got replacement tubes, still no joy. We then assumed it was the whole light but I wanted to check the supply before I when any further.

The supply is 214VAC across L-N and L-E and negligible across E-N. This is the same on all sockets also. Is this the fault? All other strip lights in the building are OK.

An electrician?? has suggested that the flickering light is due to a power surge in the area and the strip light is not suitable and we should change the lighting for something more appropriate. I'm not sure he checked the supply.

Any suggestions?

Thanks in advance

 

[westie101]

Assuming the building has a separate supply and the group pays the bill

During the week contact your local DNO and register a complaint of Low Volts. They will fit a recorder and assess the situation.
I below limits they will correct the situation if it is on their network

All this will be at nil cost!

I would suggest that the electrician actually has little idea particularly blaming power surges!

 

[Mr Smyth]

Thanks for your reply

Is a DNO our supplier?

 

[securespark]

Hi

Sounds like you either have a supply outside the designated parameters or possibly a fault somewhere, bringing the voltage down.

I am a Leader too. Our HQ has a three phase supply - has yours? If so, are the sockets and lights off the same phase?

If you do have 3 phase, have you got 214V to N & E on the others?

However, I would think that if the lower voltage was causing this problem to one of your fittings, it would cause all of them to struggle to strike. Do your fittings have HF control gear or old fashioned chokes?

I assume you have fitted replacement tubes of a value suited to the control gear and starters matched to the tubes?

It's best to swap them both together.

Why has your spark suggested the fitting is not appropriate? It sounds to me a bit like he's not sure what's going on and is clutching at straws.

 

[plugwash]

The voltage at the intake from the distribution network to your installation should be between 216.2V and 253V. Volt drop in the installation can reduce the voltage at the point of use further. So while 214V is certainly on the low side equipment should be able to deal with it.

I would suggest replacing the balast in the fitting with an electronic model (which tend to be more tolerant of input voltage variation than traditional magnetic ones). I would also check the datasheet before buying to make sure that the vendor considered 214V to be within the acceptable range (I would expect them to but it pays to check).

I would also want to investigate the reason for the low voltage, is the hut fed directly from the DNO or from some private distribution system? Low voltage could just be a combination of heavy loads and long cables, but it could also be an indication of a fault somewhere.

 

[JohnW2]

The voltage at the intake from the distribution network to your installation should be between 216.2V and 253V. Volt drop in the installation can reduce the voltage at the point of use further. So while 214V is certainly on the low side equipment should be able to deal with it.

That may be the case, but I suspect that might, as a generalisation, be wishful thinking. Although the supply is allowed to be anything between 216.2V and 253V (and the the regs are deemed to have been satisfied if, due to voltage drop within the installation, the voltage supplied to lighting equipment is as much as 6.9V below that - hence theoretically down to 209.3V), I don't think that in any way guarantees that any particular piece of equipment will function satisfactorily over that range of voltages, does it?

Kind Regards, John

 

[westie101]

I don't think that in any way guarantees that any particular piece of equipment will function satisfactorily over that range of voltages, does it?

If CE marked and recently made it should ............

 

[JohnW2]

I don't think that in any way guarantees that any particular piece of equipment will function satisfactorily over that range of voltages, does it?

If CE marked and recently made it should ............

That's interesting - but how does that work? Are you saying that all countries within the EU have the same guidance regarding within-installation VD as that which exists in BS7671 - such that all lighting equipment has to work satisfactorily down to 209.3V, and all other equipment down to 204.7V ?

Kind Regards, John

 

[AndyPRK]

you may also want to check the batteries in your meter

and see if you get a more sensible reading at home

 

[westie101]

That's interesting - but how does that work? Are you saying that all countries within the EU have the same guidance regarding within-installation VD as that which exists in BS7671 - such that all lighting equipment has to work satisfactorily down to 209.3V, and all other equipment down to 204.7V ?

My understanding is that overall in Europe declared voltage has been standardized at 230=/- 10%.

In the UK to cater for our original 240V nominal voltage it is 230 +10/-6
In other states to cater for their original nominal voltage of 220V it is the opposite at +6/-10.


So from that anything sold and CE certified must operate over that range.

But discussions over the last amendment to BS 7671 revealed that the EU was involved with some degree of standardization so it is possible and quite likely that the voltage limits regarding installations could well be standardized.

We were told by colleagues who had been involved with the nominal voltage discussions as part of the group that advised on them for the UK that the original intent for the UK was (and could still be, though postponed) was +/- 10%.
Which adds further weight to my supposition as I see it

 

[JohnW2]

My understanding is that overall in Europe declared voltage has been standardized at 230=/- 10%. ... In the UK to cater for our original 240V nominal voltage it is 230 +10/-6
In other states to cater for their original nominal voltage of 220V it is the opposite at +6/-10. ... So from that anything sold and CE certified must operate over that range.

Fair enough, but what I said went a bit further than that. You appear to be saying that anything CE marked has to work over the range of declared voltages, which is fair enough. However, my point was that it is not necessarily the case that a particular piece of equipment would work satisfactorily when the maximum 'permitted' within-installation VD (UK guidelines 6.9V for lighting, 11.5V for everything else) occurred in an installation whose supply was already at the bottom of the permitted ('declared') range. Given that VD guidelines/rules probably vary between countries, equipment could only be guaranteed to work satisfactorily throughout Europe if it was required to be able to work in the country which allowed the greatest within-installation VD.

But discussions over the last amendment to BS 7671 revealed that the EU was involved with some degree of standardization so it is possible and quite likely that the voltage limits regarding installations could well be standardized. ... We were told by colleagues who had been involved with the nominal voltage discussions as part of the group that advised on them for the UK that the original intent for the UK was (and could still be, though postponed) was +/- 10%. Which adds further weight to my supposition as I see it

Interesting. Are you suggesting that there might also be an attempt to standardise guidelines/rules as regards within-installation VDs? A combination of 230V±10% and the 11.5V 'permitted' UK (non-lighting) VD would mean that non-lighting equipment would have to work down to 195.5V in UK.

Kind Regards, John

 

[westie101]

Think it through.

The declared voltage and limits only apply at the supply incoming position.
So there will always be the situation where points on the installation will be below this figure.
i.e. given the situation given in the OP if the supply voltage at the meter position is within limits even if only .1V above the minimum, it is legal and the DNO need take no action.

That figure needs to be known to allow a standard for portable equipment to be produced otherwise each individual state could have a different lower voltage figure, in fact it is quite possible that the "equipment" lower limit Europe wide may be even lower that would be expected to be seen in the UK.

I'm not saying on anything of this "does" but it seems logical to me.

 

[stillp]

Most standards for equipment require correct operation between +10% and -15% of nominal supply voltage.

 

[JohnW2]

Most standards for equipment require correct operation between +10% and -15% of nominal supply voltage.

Interesting - that would just cope with the -10% (supply) plus -5% (within-installation VD) situation.

Kind Regards, John

 

[JohnW2]

Think it through. ... The declared voltage and limits only apply at the supply incoming position. So there will always be the situation where points on the installation will be below this figure. i.e. given the situation given in the OP if the supply voltage at the meter position is within limits even if only .1V above the minimum, it is legal and the DNO need take no action.

No argument about any of that - but it's not what I was saying in the post you picked up on. I was saying that, as far as I was aware (perhaps incorrectly, in view of what stillp now tells me), there was no guarantee that a particular equipment would function satisfactorily if the supply were at the minimum permitted level (so that DNO 'need take no action') and there was also a substantial (perhaps 'maximum permitted') VD within the installation.

Kind Regards, John