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ok just put some halogen spot lights up in the kitchen and when switched on the 1 furthest away from the conexion comes on noticably last and is not as bright as the 1st one in fact the 3 furthest away are dimmer , these are the low voltage type and i have had to extend the wiring to get the spacing i wanted ?
could my wiring be dodgy or too thin
any lecys out there who can help ?
could my wiring be dodgy or too thin
any lecys out there who can help ?
In reply to koolkat: they in Parallel or Series, the current will flow through the path of least resistance, hence the brighter at one end to the other! no idea how to fix this sorry, i can only remember glimmers of my Electrical course work! im a mech eng, not a sparky!
Jess.x
Jess.x
In reply to koolkat:
Are they attached to a transformer? Check the rating versus the wattage of the bulbs in the lamps. You may be asking too much of your transformer.
Are they attached to a transformer? Check the rating versus the wattage of the bulbs in the lamps. You may be asking too much of your transformer.
In reply to koolkat:
You are not supposed to extend the cables, if you do they will be dimmer. Try using a thicker cable if you really must extend them, though most have their own transformer now so should not be a problem. You cannot use a dimmer switch on them at all.
Check all the connections as well in case one is loose or broken.
You are not supposed to extend the cables, if you do they will be dimmer. Try using a thicker cable if you really must extend them, though most have their own transformer now so should not be a problem. You cannot use a dimmer switch on them at all.
Check all the connections as well in case one is loose or broken.
In reply to koolkat: Right then: If the lights are running from one transformer, then the cabling on the out put side (12volt) needs to be at least 2.5mm2, If you can do it it is better practice to have one transformer per light fitting, thus keeping the low voltage cable runs to a minimum. These lights can be dimmed if the transformers are the electronic type, and state on them Dimmable..
Your circuit breaker for the lighting in your kitchen should be a B type 6Amp....
Your circuit breaker for the lighting in your kitchen should be a B type 6Amp....
In reply to all u leckys :
so even if put thicker cable (assuming ive put too thin ) the furthest away
are going to be dimmer if they all work off 1 transformer,
am i right in thinking
so even if put thicker cable (assuming ive put too thin ) the furthest away
are going to be dimmer if they all work off 1 transformer,
am i right in thinking
In reply to koolkat: Sounds like you have wired them in series. Does the negative wire from bulb one go to the positive of bulb 2 and so on? If so, this is why you are witnessing problems.
What you need to do is wire all the bulb positives up to the positive wire and all the bulb negatives to the negative wire so that you end up with something that on paper looks like a ladder. Should solve your problem.
What you need to do is wire all the bulb positives up to the positive wire and all the bulb negatives to the negative wire so that you end up with something that on paper looks like a ladder. Should solve your problem.
In reply to jon : to extend the wires from each lamp ive cut the wire and put in conecters matching blue to blue and brown to brown , there is no earth it looks to me that they are wired in parallel ( the lader i guess )
In reply to Jon Dittman:
Usually they are AC so do not tend to have + or - on the lamp connectors.
To be wired in series, there would have to be only one wire (instead of 2 core) between each of the lamps with a single core wire going to the transformer from each end lamp. This is unlikely but possible. It is quite likely that you have used wire which is too small and you do get a noticeable volt drop with low voltages and thin cables.
Also, have you checked that the 'bulbs' are the same wattage?
> (In reply to koolkat) Sounds like you have wired them in series. Does the negative wire from bulb one go to the positive of bulb 2 and so on? If so, this is why you are witnessing problems.
>
> What you need to do is wire all the bulb positives up to the positive wire and all the bulb negatives to the negative wire so that you end up with something that on paper looks like a ladder. Should solve your problem.
>
> What you need to do is wire all the bulb positives up to the positive wire and all the bulb negatives to the negative wire so that you end up with something that on paper looks like a ladder. Should solve your problem.
Usually they are AC so do not tend to have + or - on the lamp connectors.
To be wired in series, there would have to be only one wire (instead of 2 core) between each of the lamps with a single core wire going to the transformer from each end lamp. This is unlikely but possible. It is quite likely that you have used wire which is too small and you do get a noticeable volt drop with low voltages and thin cables.
Also, have you checked that the 'bulbs' are the same wattage?
In reply to all: have changed the bulbs from 20w to 35w they are in parallel so if i up the wire thickness that will help , they are 12v lamps
what about changing the transformer , or are they not readily available ?
thanks all for your help
what about changing the transformer , or are they not readily available ?
thanks all for your help
In reply to koolkat: Off topic, but on the subject of halogen bulbs...
I thought that they were supposed to last longer than standard spot bulbs...
I was pretty pee'd off to switch my kitchen and dining room lights on last night to see 1 bulb from both sets of 4 bulbs have blown! They've only been there for 12 weeks!!
I thought that they were supposed to last longer than standard spot bulbs...
I was pretty pee'd off to switch my kitchen and dining room lights on last night to see 1 bulb from both sets of 4 bulbs have blown! They've only been there for 12 weeks!!
In reply to Bingly Bong:
I've always found them worse!
IIRC You should make sure you don't touch the glass of the bulb as any slight grease from your fingers make them more likely to go as they become very hot. Same for car headlight bulbs.
I've always found them worse!
IIRC You should make sure you don't touch the glass of the bulb as any slight grease from your fingers make them more likely to go as they become very hot. Same for car headlight bulbs.
In reply to Bingly Bong:
I've always found halogen bulbs fine and long lasting, with the exception of those GU10 ones with the built in transformer. Used to last on average about a month each in my shoddily wired old place.
I've always found halogen bulbs fine and long lasting, with the exception of those GU10 ones with the built in transformer. Used to last on average about a month each in my shoddily wired old place.
In reply to Swig:
If the lamps are driven from an electronic transformer a run of the mill multimeter won't work as the output from the transformer will be high frequency as a pose to 50Hz from a conventional transformer
> (In reply to koolkat)
>
> Use a multimeter and test the voltage across each bulb?
>
> Use a multimeter and test the voltage across each bulb?
If the lamps are driven from an electronic transformer a run of the mill multimeter won't work as the output from the transformer will be high frequency as a pose to 50Hz from a conventional transformer
In reply to koolkat: so perhaps i shud just get mains voltage spots assuming this problem wont arise with a drop of light output,
In reply to Andy Hudson:
Yes. The OP didn't make it clear whether he had a basic transformer or a switched mode power supply.
Yes. The OP didn't make it clear whether he had a basic transformer or a switched mode power supply.
In reply to swig : cant read it too dark in the kitchen will check that tomorrow , dont think i had this problem wen i had 20w bulbs in but needed more light so put in 35w bulbs in then noticed the problem , very noticable that the end lamps com on later than the others
In reply to koolkat:
You should get some lights!
> (In reply to swig ) cant read it too dark in the kitchen
You should get some lights!
In reply to swig : maybe some nice low voltage spot 1s ;-0
In reply to koolkat:
>We've just had some electrical work done to our water heater. The supervisor was complaining to us about all the new health & safety rules. It appears that it is now actually illegal to do your own electrical or gas repairs unless you are registered as a qualified, licenced person.
I don't want to put you off doing it yourself & if it is done correctly there won't be a problem. But if something does go wrong, e.g. a fire, any insurance you have will be invalid if they find out that you did thr job yourself.
>We've just had some electrical work done to our water heater. The supervisor was complaining to us about all the new health & safety rules. It appears that it is now actually illegal to do your own electrical or gas repairs unless you are registered as a qualified, licenced person.
I don't want to put you off doing it yourself & if it is done correctly there won't be a problem. But if something does go wrong, e.g. a fire, any insurance you have will be invalid if they find out that you did thr job yourself.
In reply to koolkat:
not in scotland its not illegal ,
on another note any one want to buy 5 low voltage spot lites work ok with 20w lamps not ok with 35w lamps iam gona put , mains 1s in
not in scotland its not illegal ,
on another note any one want to buy 5 low voltage spot lites work ok with 20w lamps not ok with 35w lamps iam gona put , mains 1s in
In reply to koolkat:
Just get another transformer and split the load, that is almost certainly the problem. You didn't say you had uprated the bulbs in your first posting.
Just get another transformer and split the load, that is almost certainly the problem. You didn't say you had uprated the bulbs in your first posting.
In reply to D.Musgrave:
Or just swear blindly they were done before the new laws due to a lack of evidence suggesting otherwise!
> (In reply to koolkat)
>
But if something does go wrong, e.g. a fire, any insurance you have will be invalid if they find out that you did thr job yourself.>
Or just swear blindly they were done before the new laws due to a lack of evidence suggesting otherwise!
In reply to sutty :
ok your winning on advice here ( thanks ) ive just taken out 3 lamps furthest away and left the 2 closest in ( 2 x 35w ) and there fine
original lamps were 3 x 20w
however when i leave in the 2 furthest away 35w lamps and remove the other 3 , same loading w wise as 2 closest i guess , they still are not as bright ?
ok your winning on advice here ( thanks ) ive just taken out 3 lamps furthest away and left the 2 closest in ( 2 x 35w ) and there fine
original lamps were 3 x 20w
however when i leave in the 2 furthest away 35w lamps and remove the other 3 , same loading w wise as 2 closest i guess , they still are not as bright ?
In reply to koolkat: original lamps were 5 x 20w
In reply to koolkat:
5x20=100, probably the rating for the transformer.
3x35=105, safe limit of transformer for full lights.
5x20=100, probably the rating for the transformer.
3x35=105, safe limit of transformer for full lights.
In reply to sutty: but when i left 3 in furthest away they wernt full brightness
In reply to Bingly Bong: The bulbs that come with sets and fittings are generally cheapy ones that aren't too clever. Top quality bulbs will cost you about a fiver each but will last years. We had some in our kitchen at our last house and got 7 years out of them. Make sure you replace them with the same wattage so as not to run in to trouble like the OP here.
In reply to D.Musgrave:
Actually, under part P of the building regs you can do some electrical work yourself but unfortunately installing low voltage lighting is not one of them, it should be done by a qualified sparks. I don't think it makes a huge deal of difference with house insurance at the moment though as insurers don't ask for electrical test certificates to insure you.
> (In reply to koolkat)
>
> >We've just had some electrical work done to our water heater. The supervisor was complaining to us about all the new health & safety rules. It appears that it is now actually illegal to do your own electrical or gas repairs unless you are registered as a qualified, licenced person.
> I don't want to put you off doing it yourself & if it is done correctly there won't be a problem. But if something does go wrong, e.g. a fire, any insurance you have will be invalid if they find out that you did thr job yourself.
>
> >We've just had some electrical work done to our water heater. The supervisor was complaining to us about all the new health & safety rules. It appears that it is now actually illegal to do your own electrical or gas repairs unless you are registered as a qualified, licenced person.
> I don't want to put you off doing it yourself & if it is done correctly there won't be a problem. But if something does go wrong, e.g. a fire, any insurance you have will be invalid if they find out that you did thr job yourself.
Actually, under part P of the building regs you can do some electrical work yourself but unfortunately installing low voltage lighting is not one of them, it should be done by a qualified sparks. I don't think it makes a huge deal of difference with house insurance at the moment though as insurers don't ask for electrical test certificates to insure you.
In reply to teflonpete:
anyone can do wiring in their home as long as they get a part p registered sparky to commission it before first use
anyone can do wiring in their home as long as they get a part p registered sparky to commission it before first use
In reply to koolkat:
You may have 2 problems:
- the transformer/power supply is not enough to cope with more than 3 35W bulbs.
- your wires are too thin/runs too long.
Sutty's idea of getting another transformer and using that two run half of your bulbs is a good one. You can deal with both problems at once - the new transformer can be closer to the other lights. I think he is/was an electrician which is why he knows!
You may have 2 problems:
- the transformer/power supply is not enough to cope with more than 3 35W bulbs.
- your wires are too thin/runs too long.
Sutty's idea of getting another transformer and using that two run half of your bulbs is a good one. You can deal with both problems at once - the new transformer can be closer to the other lights. I think he is/was an electrician which is why he knows!
Total power of bulbs is 5 x 35W = 175W.
Your cabling has to cope with 175W/12V = about 15A. That's a reasonable current so you want a decent size cable. Then I googled and found this calculator:
http://www.tlc-direct.co.uk/Technical/Lighting/VoltageDrop.html
Your cabling has to cope with 175W/12V = about 15A. That's a reasonable current so you want a decent size cable. Then I googled and found this calculator:
http://www.tlc-direct.co.uk/Technical/Lighting/VoltageDrop.html
In reply to sutty:
Most/all transformers are now dimmable . I ve fitted hundreds of these usually wiyh 50 watt dc bulbs / transformers with no problems. 35 WATT are a bit dull unless you have a lot .
> (In reply to koolkat)
>
> You are not supposed to extend the cables, if you do they will be dimmer. Try using a thicker cable if you really must extend them, though most have their own transformer now so should not be a problem. You cannot use a dimmer switch on them at all.
>
> Check all the connections as well in case one is loose or broken.
>
> You are not supposed to extend the cables, if you do they will be dimmer. Try using a thicker cable if you really must extend them, though most have their own transformer now so should not be a problem. You cannot use a dimmer switch on them at all.
>
> Check all the connections as well in case one is loose or broken.
Most/all transformers are now dimmable . I ve fitted hundreds of these usually wiyh 50 watt dc bulbs / transformers with no problems. 35 WATT are a bit dull unless you have a lot .
In reply to Swig:
Wrong ! If you have ten 50 watt lights this equals a 500 WATT load . A rough calculation equates to 4 amp per kilowatt . This is found by deviding your load 1000 watts by your supply voltage 240 volts . So your ten lights equal roughly a 2/3 AMP LOAD . Domestic lighting circuits are normally protected by a 6amp circuit breaker . 1.5 twin and earth cable is more than adequate to feed your transformers . The 240 volt connection should then be made in a joint box . There is no need to extend the transformer cables . Have you used fire rated downlights which are now regulation if you have accomodation in the rooms above ? Complicated isnt it . Thats why i take my car to a garage to have it fixed and people ring me to sort their lights !!
> Total power of bulbs is 5 x 35W = 175W.
>
> Your cabling has to cope with 175W/12V = about 15A. That's a reasonable current so you want a decent size cable. Then I googled and found this calculator:
>
> http://www.tlc-direct.co.uk/Technical/Lighting/VoltageDrop.html
>
> Your cabling has to cope with 175W/12V = about 15A. That's a reasonable current so you want a decent size cable. Then I googled and found this calculator:
>
> http://www.tlc-direct.co.uk/Technical/Lighting/VoltageDrop.html
Wrong ! If you have ten 50 watt lights this equals a 500 WATT load . A rough calculation equates to 4 amp per kilowatt . This is found by deviding your load 1000 watts by your supply voltage 240 volts . So your ten lights equal roughly a 2/3 AMP LOAD . Domestic lighting circuits are normally protected by a 6amp circuit breaker . 1.5 twin and earth cable is more than adequate to feed your transformers . The 240 volt connection should then be made in a joint box . There is no need to extend the transformer cables . Have you used fire rated downlights which are now regulation if you have accomodation in the rooms above ? Complicated isnt it . Thats why i take my car to a garage to have it fixed and people ring me to sort their lights !!
In reply to koolkat: moved the transformer closer for 3 lights
and got a new transformer for 2 lights all happy now
thanks for the help
and got a new transformer for 2 lights all happy now
thanks for the help
In reply to mick o the north:
>Have you used fire rated downlights which are now regulation if you have accomodation in the rooms above ?
Never mind that, I found molten fibreglass dripping from the sides of some spots in a flat roof extension. Nowhere for the heat to dissipate amongst all that insulation, almost touching in places.!!
I take it you are a spark as well, mail me if you don't want to say on here so I can add you to the list of tradespeople that are of the trusted type when giving information. It is nice to know who knows what they are doing and who is talking bollox.
>Have you used fire rated downlights which are now regulation if you have accomodation in the rooms above ?
Never mind that, I found molten fibreglass dripping from the sides of some spots in a flat roof extension. Nowhere for the heat to dissipate amongst all that insulation, almost touching in places.!!
I take it you are a spark as well, mail me if you don't want to say on here so I can add you to the list of tradespeople that are of the trusted type when giving information. It is nice to know who knows what they are doing and who is talking bollox.
In reply to sutty:
I've made vented boxes in the past specifically for that purpose :0)
> (In reply to mick o the north)
>
> >Have you used fire rated downlights which are now regulation if you have accomodation in the rooms above ?
>
> Never mind that, I found molten fibreglass dripping from the sides of some spots in a flat roof extension. Nowhere for the heat to dissipate amongst all that insulation, almost touching in places.!!
>
> >Have you used fire rated downlights which are now regulation if you have accomodation in the rooms above ?
>
> Never mind that, I found molten fibreglass dripping from the sides of some spots in a flat roof extension. Nowhere for the heat to dissipate amongst all that insulation, almost touching in places.!!
I've made vented boxes in the past specifically for that purpose :0)
>
> I take it you are a spark as well, mail me if you don't want to say on here so I can add you to the list of tradespeople that are of the trusted type when giving information. It is nice to know who knows what they are doing and who is talking bollox.
> I take it you are a spark as well, mail me if you don't want to say on here so I can add you to the list of tradespeople that are of the trusted type when giving information. It is nice to know who knows what they are doing and who is talking bollox.
In reply to mick o the north:
Right!
This is the 12V bit of the low voltage lighting not the 240V bit
P = IV
(5 * 35) = I / 12
I = 175/12 = 14.58A
Right!
This is the 12V bit of the low voltage lighting not the 240V bit
P = IV
(5 * 35) = I / 12
I = 175/12 = 14.58A
In reply to mick o the north:
There was the odd complicated bit in my 4 year Electronic Engineering degree!!
Take it you didn't read the thread quite closely enough.
> Complicated isnt it . Thats why i take my car to a garage to have it fixed and people ring me to sort their lights !!
There was the odd complicated bit in my 4 year Electronic Engineering degree!!
Take it you didn't read the thread quite closely enough.
In reply to Swig: wrong !!!!! The V in your formula should be the supply AC VOLTAGE 240 volts . Your V wrongly refers to the dc voltage on the load side of your transformer ie 12 VOLTS DC . If you had a load of 14 amps plus in any domestic lighting circuit you have got BIG problems .
In reply to mick o the north:
No, It's right.
It's AC coming out of a transformer as well unless it is rectified to DC. There's no need to do that for lighting.
But either way when we quote AC voltages we are talking RMS values not peak - so the calculation is the same.
I was surprised myself at the current - which is why I was glad the web link agreed with me.
The current flowing in the primary (240V RMS) side of the transformer will be as you calculate plus a fraction for losses.
No, It's right.
It's AC coming out of a transformer as well unless it is rectified to DC. There's no need to do that for lighting.
But either way when we quote AC voltages we are talking RMS values not peak - so the calculation is the same.
I was surprised myself at the current - which is why I was glad the web link agreed with me.
The current flowing in the primary (240V RMS) side of the transformer will be as you calculate plus a fraction for losses.
The losses due to heating in a cable are proportional to the square of the current.
P = IV and V = IR so P = (I x I)R.
That's why the National Grid is run with such high voltages - to reduce power loses to heat in the cables.
In reply to Swig: Britains leading lighting manufacturer assures me as i thought that it is high frequency dc on the secondary side of the transforner . They are rated at 0.23 amps .
In reply to Swig:
The cables on teh supply side should not have to cope with more than 6 amps if the design of the installation is correct . IE 1.5 MM twin . The cables on the load side are 0.5 / 0.75 mm .
> Total power of bulbs is 5 x 35W = 175W.
>
> Your cabling has to cope with 175W/12V = about 15A. That's a reasonable current so you want a decent size cable. Then I googled and found this calculator:
>
> http://www.tlc-direct.co.uk/Technical/Lighting/VoltageDrop.html
>
> Your cabling has to cope with 175W/12V = about 15A. That's a reasonable current so you want a decent size cable. Then I googled and found this calculator:
>
> http://www.tlc-direct.co.uk/Technical/Lighting/VoltageDrop.html
The cables on teh supply side should not have to cope with more than 6 amps if the design of the installation is correct . IE 1.5 MM twin . The cables on the load side are 0.5 / 0.75 mm .
In reply to mick o the north:
Power = Current x Voltage
And that voltage can be either AC RMS or DC.
If you've got 12V and 0.23A you can run a 2.8 watt bulb.
Where have I got the calculations wrong?
Power = Current x Voltage
And that voltage can be either AC RMS or DC.
If you've got 12V and 0.23A you can run a 2.8 watt bulb.
Where have I got the calculations wrong?
In reply to mick o the north:
No, I'm talking about the lighting side not the supply side. 14A in a lighting circuit at 240V would be crazy.
No, I'm talking about the lighting side not the supply side. 14A in a lighting circuit at 240V would be crazy.
In reply to Swig: We may be talking about different things !! But back to th original topic the cable size should never need to be increased providing the house is wired correctly using 1.5 cable for the lighting . The lighting transformers will come pre wired with the correct sized cable . These should sit locally to each fitting and be reasonably well ventilated ie not covered in rockwool .
In reply to mick o the north:
Yep I think so.
Anyway sounds like he's muddled through and got his lights working by adding another transformer in. Hopefully safely!
Yep I think so.
Anyway sounds like he's muddled through and got his lights working by adding another transformer in. Hopefully safely!
In reply to the inspiral carpet:
Actually, some councils will inspect at first fix and give you a test sheet to fill out after second fix and issue you with a building control certificate to cover the part P requirement. Normally costs about £100 - £150. An inspection and test by a qualified sparks would probably cost a little more but, understandably, many sparks are unwilling to certify other peoples work.
> (In reply to teflonpete)
>
> anyone can do wiring in their home as long as they get a part p registered sparky to commission it before first use
>
> anyone can do wiring in their home as long as they get a part p registered sparky to commission it before first use
Actually, some councils will inspect at first fix and give you a test sheet to fill out after second fix and issue you with a building control certificate to cover the part P requirement. Normally costs about £100 - £150. An inspection and test by a qualified sparks would probably cost a little more but, understandably, many sparks are unwilling to certify other peoples work.
In reply to teflonpete: That was for a complete house rewire, it would probably be cheaper for a smaller installation.
In reply to teflonpete:
When I did the wiring when we converted the loft in the last house I just told building control I was extending the existing ring mains. All we had was a £50, 5 minute inspection at the end of the work and hey presto - Part P certificate.
When I did the wiring when we converted the loft in the last house I just told building control I was extending the existing ring mains. All we had was a £50, 5 minute inspection at the end of the work and hey presto - Part P certificate.
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