Paging the sparkies

My woodwork workshop has two fluorescent tubes, wired through a circuit
breaker. They're on a separate circuit to the sockets.

Last week, I was using a circular saw when the lights suddenly went out
(both of them). I thought the circuit breaker had tripped, but it
hadn't.

Checking this evening reveals that power is getting to both tubes. The
tubes themselves seem fine, so I'm guessing that something has killed
the "starter" circuits in the lights. These fittings don't seem to have
separate starter thingies (as I believe they are known).

Is it likely that using the saw has done something nasty to the
circuits?

Any ideas very welcome.

 

"Something Nasty In The Woodshed."

Dunno. I recently added two more new fluorescent tube fittings to the
garage wired in to the existing lighting circuit. They have separate
standard little starter can jobbies. Yours must be posh.

If they are on different circuits could a power surge still have
affected them? Otherwise perhaps a strange resonance set up in starter
PCBs or what ever by the noise from the saw. Pretty unlikely that would
kill both at the same instant though. Rogue electrons more likely.

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MCB's? Or RCD?

Presumably it is MCB's then if the saw was still powered?

More info required.
Is there power to the sockets?
Or was the only fault a trip of the miniature circuit breaker?
A MCB tripping is usually a overload, rather than a live to earth fault.
A live to earth will cause the RCD to trip (you have got a RCD?)

Probaby knackered ballasts. They are crap. I used to change one a week
or so in my old job from a pool of 200 lights. £10ish new, so change the
whole light fitting rather than trying to repair the existing fitting.
I'm just fitting today a couple I've bought, same as these:
<http://www.tlc-direct.co.uk/Products/GLWP236.html>
Though I paid £15ea from my local electrical dealer. Good quality, water
and dust proof, ideal for a garage.

Alan.

 

Using the patented Mavis Beacon "Hunt&Peck" Technique, A.Lee

MCBs. There's an RCD at the main feed to the workshop.

No circuit breakers tripped at all.

Both lights died at exactly the same time.

 

New lights needed.
Possibly the saw was drawing a lot of current, the volts dropped a bit,
the lights then tried to draw more amps, as the volts were low, to stay
alive, then overheated, and possible damaged the ballast.
All the above could be bollocks, but is my theory!

I'd check to see what size cable is feeding the workshop firstly. Has it
got big enough conductors for the length of cable?
If that is fine, then check each terminal connection to make sure they
are all tight - very easy to have a loose connection that causes
overheating.
If you want to give me length/power consumption I can check it is rated
correctly.

Alan.

 

Possibly if the saw draws a large amount of power, you could be
causing a power surge when switching it off ,this might fry the
crcuits of the electronic starters .

 

How did you check that power is getting to the tubes?

My guess is no neutral.

 

Are they "2D" or some other form of compact, folded or circular tube?

If the tube is an assembly with plastic bits, check how many pins its got -
2 for built in starter, 4 for starter in the light fitting.

Just guessing, but if you can't find a starter on the fitting, its a 2 pin
only and you can only use 2 pin tubes. AFAIK you can use a 2 pin tube on a 4
pin fitting.

It wouldn't hurt to distribute a few surge limited socket strips around the
workshop.

 

which suggests a wiring problem - what did you check the power to the light
units with? Did you measure across the L-N feeds with a meter or just look
for hot wires with a neon screwdriver? If the latter, check the neutral
wiring back to the panel.

 

Cheapo electronic ballasts knackered by dirty power spikes from the saw.

 

Using the patented Mavis Beacon "Hunt&Peck" Technique, A.Lee

Thanks. The cable is 2.5mm diameter conductors in a shielded cable. It's
about 12 metres long. Current draw would have been pretty small. The
saw's a hand-held thing. I'm not sure what its rating is, but it's
certainly not fused above 13 amps.

Other than that, two fluorescent tubes and the radio.

 

Easy way to check , meter out the switched live to neutral then
switched live to earth , if either are broken it will show 0 volts

 

Using the patented Mavis Beacon "Hunt&Peck" Technique, wessie

Meter, it's reading 230V across the feeds.

 

Using the patented Mavis Beacon "Hunt&Peck" Technique, Grimly Curmudgeon

That's what I wondered.

 

Using the patented Mavis Beacon "Hunt&Peck" Technique, John F

Meter. And wiring another lamp to the feed gets light.

 

Thats fine, that cable should be able to handle 29A continuous.
You'll only be losing around 2.8v as voltage drop at 13A over 12metres,
so voltage drop is not an issue. Do check that all connections are tight
occasionally.
Typical hand held circular saws are 1200 - 1800 w, so well within the
limits for consumption for that cable. I'm presuming it is a radial
circuit only feeding the workshop?
You should have a 20A or lower MCB for that.
Note that it will not trip at 20a, but more like 30a after a couple of
minutes. This allows for short over-amps such as starting a large motor
etc.

Main theory is still right. Cheap flourescent ballasts that have blown.
Either drawing too much current, getting too hot, or a very short spike
that burnt them out.

Alan.

 

www.thechocolateteapotshop.com

 

They've served me well over the years, if you don't want any that's your
look out.

 

We've got those in the workshop and in the booth for safety reasons as they
don't create sparks (supposedly). We have no power outlets in the booth, but
in the workshop it's not unusual for them to go titsup when a particularly
heavy load is drawn. That's usually when we're using infra red heaters and
the compressor fires up. It's like the electric chair and all the lights go
dim for a split second. Some of them go dim forever, but thankfully, it's
not a regular thing.

Or just spiked the current. I dunno, but it wouldn't surprise me to discover
the saw was the sawce.

Ditch that kind of light and get the ones with separate (and replaceable)
starters. The starter types seem immune to power surges. At least at our
place anyway.

 

Until the clips holding the clear front deteriorate and fucking fail. I had
a clear front drop on me a couple of years ago

They are good though, but dear at 15 quid a pop (ha) when you consider that
I got probably 30 or 40 from a firm that moved premises. Cost me the huge
amount of **** all but collection.

I've got to still put a few up in my garage at home before they're all used
by the boy-chic at work.