Lighting cable through mdf

[robertybob]

I am making a lamp and I need to run the live, earth and neutral wires through a hole in 25mm mdf. The outer sheath is removed due to a switch.

Everything works until the wires go through the mdf. Then the live has no current. The hole is about 6mm diameter.

What's happening?

Thanks.

 

[littlespark]

Photo please?

It could simply be that a connection has come loose with pulling the cable through.

Technically, you don’t get a current unless there’s a working load on the circuit, like the lamp.

You should get the supply voltage between live and neutral though.


Making lamps DIY can cause problems especially if you’re selling them on.
They need to be tested for safety with the right equipment. (PAT)

 

[DPG]

Some continuity tests of each conductor would be useful. With the power off obviously.

Once you have the results we can decide whether some voltage tests would be worth doing.

And as above, photos would be useful. Were the wires tight? Did they need pulling hard?

 

[robertybob]

Many thanks for the replies. I've done some further extensive tests and it seems that a metal handle that is attached to the mdf is a couple of millimetres too close to the switch. Far enough to have no chance of touching any wires or switch but close enough to interfere.

Need to move them apart slightly and maybe insulate to fix the problem. Unexpected design flaw.

In reference to earlier point, this will be PAT tested.

Appreciate the prompt responses here.

 

[DPG]

Many thanks for the replies. I've done some further extensive tests and it seems that a metal handle that is attached to the mdf is a couple of millimetres too close to the switch. Far enough to have no chance of touching any wires or switch but close enough to interfere.

Need to move them apart slightly and maybe insulate to fix the problem. Unexpected design flaw.

In reference to earlier point, this will be PAT tested.

Appreciate the prompt responses here.

I find it hard to believe that a metal handle is interfering with the switch. Photos would be useful.

Safety is paramount.

 

[James]

is this a touch switch with no moving parts?

I have to say that i do have concerns about cables being run in such close proximity to metal parts of the fitting, especially if this is supposed to be a class 2 device.

 

[littlespark]

is this a touch switch with no moving parts?

I have to say that i do have concerns about cables being run in such close proximity to metal parts of the fitting, especially if this is supposed to be a class 2 device.

OP mentions an earth wire being run in, so I don’t think it’s class 2

 

[sunray]

I find it hard to believe that a metal handle is interfering with the switch. Photos would be useful.

Safety is paramount.

Potentially this could be the case when using a contactless device, ie voltstick.

 

[robertybob]

Apologies, just getting back to this - been a busy week.

I've finally found the issue, which was as follows.

The switch is a push switch like in a foot switch but with a bespoke mechanism for depressing the switch. When the base is assembled this switch was getting very fractionally depressed by the lever that is designed to operate it. The nature of the switch means it cuts out immediately it is depressed, not when it clicks.

So if I shave a fraction off the lever it will be sufficiently clear of the switch when in its resting position.

Many thanks to everyone getting back - not many forums work as efficiently as this one.

 

[littlespark]

“Bespoke” doesn’t sit well when we’re talking about electric switches.

Switches at mains voltage need to have been tested to a specific British standard, and something like a 3mm gap when open, and a spring for holding it closed.

Without these, the switch can cause arcing between contacts and heat up considerably, resulting in damage or injury.


Perhaps a conventional switch, made for purpose, would be better?

 

[MJPD29]

Are you selling these? Have you net the required standards? Would be an interesting one should you sell it and something go wrong.