Lighting

[Romanytony]

I have removed a strip light and replaced it with a ceiling rose and bulb holder, the wiring was straightforward as there was just black, red and earth. The new light doesn't work, with a tester held against the wire between the ceiling rose and bulb holder shows current when the switch is turned on, but the bulb doesn't light. The bulb is OK, and I can't work this one out. I don't know if the strip worked before removal.

 

[ericmark]

I have removed a strip light and replaced it with a ceiling rose and bulb holder, the wiring was straightforward as there was just black, red and earth. The new light doesn't work, with a tester held against the wire between the ceiling rose and bulb holder shows current when the switch is turned on, but the bulb doesn't light. The bulb is OK, and I can't work this one out. I don't know if the strip worked before removal.

What "tester" you need to measure between two points not single point to aerial. You says shows current which would imply you are using an ammeter which I some how think unlikely!

The centre connections (line) will have no wires.
Possible you have wires hidden in ceiling as this

is normal method and common to hide in ceiling space when replacement lamps are fitted.

 

[Romanytony]

It is a screwdriver with a bulb in the handle, when you hold the base of the handle next to a wire, it lights the bulb in the driver if a current is passing through the wire. It can also show where a break in the wire is, ie the lamp will glow as you run it along the wire until it reaches the break and the lamp goes out.

 

[rebuke]

The best thing to do with that sort of screwdriver is throw it away - they give misleading information at the best of times, dangerous information at the worst.

Get a proper multimeter, put it on an appropriate AC volts scale, and see if you get 230(ish) volts between live and neutral when the switch is on, and ~0V when off - that will tell you if it's a problem with the wiring, or with the light...

 

[ban-all-sheds]

It is a screwdriver with a bulb in the handle, when you hold the base of the handle next to a wire, it lights the bulb in the driver if a current is passing through the wire.

No - it lights up if there is a voltage relative to earth - there doesn't have to be any current flowing. As there won't be if there's no continuity in the neutral, but the live will still be at 230V relative to earth and the thing will glow.

It can also show where a break in the wire is, ie the lamp will glow as you run it along the wire until it reaches the break and the lamp goes out.

It might also light up if you rub it on a jumper.

It's probably not the sort of thing you'd want to trust your life to.

 

[Romanytony]

Good grief, I have trusted my life to this tester!!!!

Thanks for your replies, I think I understand what you are saying, even if the 'tester' is naff, it shows a current going through the wire when the switch is thrown, but that current would need to complete the circuit. So what are the two wires that connected the old strip (red & black) could they be both positive or both negative, as opposed to a switched live.

God I'm lost, I need to get a book and read up on this.

 

[ban-all-sheds]

Good grief, I have trusted my life to this tester!!!!

I wonder how long your luck will last.

Thanks for your replies, I think I understand what you are saying,

You might think you do..

even if the 'tester' is naff, it shows a current going through the wire when the switch is thrown,

No - it shows a voltage relative to earth present in the wire. Tells you nothing about current.

but that current would need to complete the circuit.

If the circuit is not completed then no current will flow, and the bulb won't light. Just like yours isn't.

So what are the two wires that connected the old strip (red & black) could they be both positive or both negative, as opposed to a switched live.

Neither will be positive or negative, as those concepts don't apply to AC.

If they are all you had at the old light then one is neutral and the other is switched live.

God I'm lost, I need to get a book and read up on this.

//www.diynot.com/forums/viewtopic.php?p=75416#75416

You might like to look at this site too: http://web.archive.org/web/20080117104446/www.kevinboone.com/electricity.html

 

[Romanytony]

My goodness, the response is fast and informative!!

Thanks for the links, I will invest and further my knowledge.

So what do you conclude is the answer to the problem?

 

[ColJack]

post a photo and we'll let you know.. we have no idea how you've wired it.. View media item 13604 View media item 13603

 

[LiamPope]

I don't know if the strip worked before removal.

So what do you conclude is the answer to the problem?

That the strip light didn't work before removal.

I mean surely nobody could have wired a pendant wrongly if only a neutral and switched live were present?

 

[ricicle]

I take it you have connected the L + N to the two outermost connections (red to the brown of the flex, black to blue)

 

[Romanytony]

The three wires from the ceiling (red, black & earth) were re-connected to the rose, earth to earth, red & black either end of the connecting strip.
The strip couldn't have worked before I took it down. The building is a huge old mill that has had loads of work done to it, including a mess of wiring when it was converted into a leisure centre.

 

[ban-all-sheds]

What is it now, and how do you come to be doing electrical work in it?

 

[Romanytony]

Ah, I see your concern, you think it is a commercial property and I am clearly not qualified as a sparks.
No, this is now my home, and all my time and money is spent trying to bring it back to a livable condition. It is a huge project and with the risk of upsetting qualified tradesmen I have learned to roof, build, plumb and rewire.
Isn't this what DIY is all about?

 

[LiamPope]

Wow! Was this a very small leisure centre, or do you now have a massive home with 4 squash courts, a 5-a-side footy pitch, swimming pool etc etc etc

I'm also a DIYer doing a full back-to-the-fabric renovation, albeit on a more modest property. Everything except the plastering and gas. It's worth pointing out that whilst things like building, roofing, carpentry, plumbing to a lesser extent, etc can be jumped straight into by a DIYer and you improve/speed up over time, electrical work really requires considerable academic knowledge before you can really hope to carry out major jobs safely and in compliance with regs. If you're running around prodding things with a neon screwdriver and unable to sort a simple light, I'd respectfully suggest you haven't yet 'learnt to rewire' and need to do a bit of book work first. Or a lot, depending on the extent of the 'rewiring' you intend to carry out yourself. At the very very least go through the Wiki here, get the OSG and a basic how-to book.

Good luck,

Liam