Fluorescent light fittings not working....

[JDLDIY]

Hi there. I bought some light fittings for my garage a few years ago and they've worked without problems until very recently when 2 have stopped working. They were from B&Q, not sure of the make, they have T8 18W tubes. I thought it would be the tubes and fitted new ones but still no joy. They have electronic ballasts. What would be the correct way to figure out what the fault is?
If the electronic ballasts have given up would they stop providing a current to the fitting entirely? Mine still have a current detectable with a testing screwdriver.

Many thanks.

 

[ban-all-sheds]

That "testing screwdriver" does not detect current, not can it.

It can only detect voltage, and even then not at all reliably.

 

[SFK]

Silly question, but wanted to check
Did they both fail at the same time?
Or did one fail and then later the other?

 

[JDLDIY]

Thanks for your replies. Yes I totally appreciate the screwdriver is a clumsy test but nonetheless it does show that some current is getting through to the fitting.

As far as I know the two that failed did so at the same time.

 

[ban-all-sheds]

Yes I totally appreciate the screwdriver is a clumsy test but nonetheless it does show that some current is getting through to the fitting.

No, it doesn't.

It does not, and cannot, detect the flow of current.

It might, sometimes, and inconsistently and inaccurately, indicate the presence or absence of some sort of voltage.

http://www.google.co.uk/search?q=electrical+circuits+101

http://www.google.co.uk/search?q=current+vs+voltage

 

[JDLDIY]

When I said current what I should have said was power I guess. Apologies for being inaccurate. I will read your links when I have a minute as I'm always keen to learn.

So how do I figure out what's wrong with these fittings?

Also, in actual fact is it a mistake to buy fluorescent fittings with electronic ballasts, should I just replace them with traditional ones with removable starters?

 

[JohnW2]

As far as I know the two that failed did so at the same time.

If true, that's a bit of a coincidence.

Do I take it that, despite what you think your screwdriver is telling you (as you have been told, it detects voltage, not current or power - and even that not reliably), electricity is actually getting to your garage (or, at least, the lighting in your garage - which may be supplied via a fused connection unit)?

Kind Regards, John

 

[AnotherTom]

Do you still have some fittings that work? the easiest way to find the problem may be to swap parts around.

Because you seem inexperienced, I want to make sure you know that turning off light fittings at their normal switch may not be sufficient to make them safe to work on. You must switch them off at the CU. In my experience this is less likely to apply to fluorescents than to traditional ceiling roses, but you still need to be careful.

Tom

 

[FrodoOne]

When I said current what I should have said was power I guess.

No. You should NOT have said "Current" - and neither should you have said "Power".

As B-A-S indicated, you should have said "Voltage"

Voltage is analogous to "Pressure"
Current is (fairly obviously) "Flow"
Voltage * Current gives the "Power" (in Watts)
A Watt is 1 Joule per Second.
(Power is the rate at which "work" is done or energy expended.)
Energy = Power * Time (e.g. One Watt for one Hour [3600 seconds] is 1 Watt/Hour or 3600 Joules)

 

[DaveHerns]

I suspect most of us knew what the OP meant.

 

[ban-all-sheds]

I will read your links when I have a minute as I'm always keen to learn.

When you read about circuits, you'll realise how misleading your screwdriver can be.

Even if it was safe and reliable, it would still not help, your "tester" would light up on the live wire in both of these scenarios:

But the light wouldn't work in both.

A multimeter, at least, is an essential tool to have if you want to work on your electrics. It is just as important to have that correct tool as it is to have screwdrivers to use on screws instead of the point of a vegetable knife, wirecutters to use instead of nail scissors, wirestrippers to use instead of teeth, and so on.

Neon screwdrivers are questionable from a safety POV as they use your body as a current path, and they are unreliable. and non-contact testers (magic wands) are also just toys. To safely check for voltage you must use a 2-pole tester, such as a proper voltage indicator or a multimeter.



This looks ideal for a household starter set - multimeter, 2-pole voltage indicator and dedicated continuity tester, all in a handy case:

https://www.beha-amprobe.com/en/products/electrical-testers/junior-set-and-kits/amprb-eu-03-a

 

[EFLImpudence]

I suspect most of us knew what the OP meant.

No, we didn't. We know what he, if correct, would and should have written because we know.
We have no idea what he actually meant.

Are you suggesting that he should not have been corrected and then helpfully educated?
If so, why, and what would be the long term outcome of such a philosophy? Wrong for ever? Others unknowingly copying it?

Where would you draw the line?

 

[John D v2.0]

People are perhaps assuming pedantry at work, but if you read ban all sheds last post he has a good point that regardless of having a voltage to earth, given a broken neutral connection, the light isn't going to work.
The op needs to know that there is a complete circuit to live and neutral, by either testing with a suitable 2 pole tester, or with an alternative appliance.
We don't even know if there is correct wiring or perhaps a polarity issue somewhere.
The most suspicious factor is they stopped working together, and if there's nothing else on the circuit would lean more towards a supply or switching fault.

 

[JohnW2]

People are perhaps assuming pedantry at work, but if you read ban all sheds last post he has a good point that regardless of having a voltage to earth, given a broken neutral connection, the light isn't going to work .... The op needs to know that there is a complete circuit to live and neutral, by either testing with a suitable 2 pole tester, or with an alternative appliance.

Indeed so. That particular post was not 'pedantry', since it was effectively explaining why even a '2-pole tester' could be misleading if (as effectively is the case with a neon screwdriver etc.) it were used to measure the potential difference between a conductor of interest and earth - since, again, that would not detect a 'broken neutral connection'.

Kind Regards, John

 

[ban-all-sheds]

We have no idea what he actually meant.

Yes we do.

He meant that his screwdriver was lighting up.