Hello all,

I'm trying to build an unusually-designed lamp from scratch. I bought
three core flex (live neutral and earth) and a basic B&Q plastic
lamp-type bulb holder - you can probably figure out my problem from
he a quick look in this group tells me that it's not unusual for a
plastic lamp holder to have no earth terminal and thats what I found
with this one.

I assume this has no safety implications to worry about and that I
should just use two core flex? Is there any way I can wire it to use
the 3 core I have already bought?

Thanks in advance...
cam

wrote in message
oups.com...
Hello all,

I'm trying to build an unusually-designed lamp from scratch. I
bought
three core flex (live neutral and earth) and a basic B&Q plastic
lamp-type bulb holder - you can probably figure out my problem from
he a quick look in this group tells me that it's not unusual for
a
plastic lamp holder to have no earth terminal and thats what I found
with this one.

I assume this has no safety implications to worry about and that I
should just use two core flex? Is there any way I can wire it to use
the 3 core I have already bought?


Assuming this isn't just a troll posting.

In having to ask such a basic question, are you sure you are capable
of building this 'lamp' safely, or should you just give up ?

I blame all these UK DIY television programmes, "Yes you can do
anything, just a wish to do it is all you need, common sense or
ability doesn't matter - you CAN do it"..... not. :~(

wrote:

I'm trying to build an unusually-designed lamp from scratch. I bought
three core flex (live neutral and earth) and a basic B&Q plastic
lamp-type bulb holder - you can probably figure out my problem from
he a quick look in this group tells me that it's not unusual for a
plastic lamp holder to have no earth terminal and thats what I found
with this one.

I assume this has no safety implications to worry about and that I
should just use two core flex? Is there any way I can wire it to use
the 3 core I have already bought?

Does your "unusually-designed lamp" have any exposed metal parts? If so
they may need earthing (I don't think you can assume that a lampholder
provides Class 2 insulation.)

Otherwise use 2-core flex, as you say. Don't attempt bodges like
cutting off the earth wire in a 3-core flex, as this may confuse someone
trying to change the plug or undertake a PAT test at a later date.

Flex used to wire directly to a lampholder should be the heat-resisting
grade to BS 6141 (you can buy this in B&Q) and not ordinary 70 deg C
rated type (BS 6500).

HTH
--
Andy

Does your "unusually-designed lamp" have any exposed metal parts? If
so
they may need earthing (I don't think you can assume that a
lampholder
provides Class 2 insulation.)

None at all...

Otherwise use 2-core flex, as you say. Don't attempt bodges like
cutting off the earth wire in a 3-core flex, as this may confuse
someone
trying to change the plug or undertake a PAT test at a later date.

This is what I was going to do - it struck me that I could just wire
the earth at the plug end and then not connect it at the bulb end.

Flex used to wire directly to a lampholder should be the
heat-resisting
grade to BS 6141 (you can buy this in B&Q) and not ordinary 70 deg C
rated type (BS 6500).

Thanks for the tip.

Jerry - I realise that it may come across as slightly dim but this is
not a troll. Attempt to get your head around the idea that not everyone
has an interest in the same topics as, I presume, yourself and have
very little 'common knowlegde' to go on in this area...

I happen to have a copy of the Reader's Digest DIY 'bible', yes, and it
encourages me to do ludicrous things like replace my consumer unit. Not
for me, and I agree with you that its breezy tone and perfect-world
diagrams probably encourage a wide range of ill-advised projects.
However, can I find an answer to a 'basic question' like this? It would
seem not.

Thanks for the replies,
cam

wrote in message
oups.com...

snip

Jerry - I realise that it may come across as slightly dim but this
is
not a troll. Attempt to get your head around the idea that not
everyone
has an interest in the same topics as, I presume, yourself and have
very little 'common knowlegde' to go on in this area...

In which case you shouldn't be contemplating doing something that
could kill if you get things wrong. Competence to do something is not
just a wish to do something...


I happen to have a copy of the Reader's Digest DIY 'bible', snip

'nough said.... :~(

:::Jerry:::: wrote:

In which case you shouldn't be contemplating doing something that
could kill if you get things wrong. Competence to do something is not
just a wish to do something...

Jeeziz, a simple question about wiring conventions and the Safety Nazis
are on you.. if only I was as serenely competent as you Jerry and as
concerned for the poor idiots around me who don't know their AC from
their DC.

I have a willingness to learn and a willingness to ask people who might
know, like those on this group. I'm sorry if this seems ill-advised or
inept to you.

I happen to have a copy of the Reader's Digest DIY 'bible', snip

'nough said.... :~(

Nicely decontextualized...

As you say, enough said.

wrote:

Jeeziz, a simple question about wiring conventions and the Safety
Nazis
are on you.. if only I was as serenely competent as you Jerry and as
concerned for the poor idiots around me who don't know their AC from
their DC.

I have a willingness to learn and a willingness to ask people who
might
know, like those on this group. I'm sorry if this seems ill-advised
or
inept to you.


If your lamp is non metal - and non conductive, just in case your
building it from carbon nanotubes - then you dont need any earth
connection. Its perfectly safe to cut the earth off and put the plastic
bulbholder onto 2 cores of the 3 core.

If a pat tester cant figure out the bleedin obvious thats his problem,
and not a danger anyway. Not all replies turn out to be accurate.

A lamp's flex should have a cordgrip to stop bare wires getting pulled
out, and the cordgrips in bulb holders are sometimes almost useless. If
your bulbholder has a less than perfect clamping of the whole of the
flex, thats both inner and outer layers, then it is wise to add a
little cordgrippage in the lamp base. The simplest way is to knot the
flex on the inside of the flex entry hole, so it cant get pulled out.
This is enough in this case because the bulbholder itself will prevent
the wires being moved about in the holder, so between the 2 youve got
whats needed.


NT

wrote:
A lamp's flex should have a cordgrip to stop bare wires getting pulled
out, and the cordgrips in bulb holders are sometimes almost useless. If
your bulbholder has a less than perfect clamping of the whole of the
flex, thats both inner and outer layers, then it is wise to add a
little cordgrippage in the lamp base. The simplest way is to knot the
flex on the inside of the flex entry hole, so it cant get pulled out.

NO. Never ever knot a mains flex. The conductors can be damaged, causing
a localised high resistance fault which can cause a fire.

Use a p-clip bolted to the lamp frame, or a proper cord grip. If nothing
better, fix a loop of cable onto itself with a cable tie so it can't be
pulled through a hole and can't be pulled tight onto itself into a knot.

Owain