PIR Sensor + Two core & earth (uninsulated)

[AdamCH]

On a similar subject. I have a fan with a timer (an inline fan in the loft) which only has space for flex.

THe fan has no earth so how acceptible is it to use the earth in the flex (1mm) as the swithed live?

 

[bernardgreen]

THe fan has no earth so how acceptible is it to use the earth in the flex (1mm) as the swithed live?

NOT acceptable. If at a later date someone replaced the fan they could assume the green/yellow core was earth and use it as such. If the new fan needed an earth because it had exposed metal parts ( or other reasons ) then they could end up with a live metal object.

If the flex was cut and the red or brown sleeve on the green/yellow was lost the chances of the above happening are even higher.

You can buy 4 core flex.

 

[DetlefSchmitz]

Use 4 core flex.

 

[EFLImpudence]

how acceptible is it to use the earth in the flex (1mm) as the swithed live?

Completely UNacceptable.

It must be connected to the CPCs (earths) at the supply end.

 

[AdamCH]

Ok I see screwfix sell 4 core so will change it over.

Is there a three core without an earth available? Seems a bodge to have a spare earth flapping about & no room in the fan to finish it in a block.

 

[JohnW2]

Ok I see screwfix sell 4 core so will change it over. Is there a three core without an earth available? Seems a bodge to have a spare earth flapping about & no room in the fan to finish it in a block.

No, no ... you must have the 'earth' there (and connected at the supply end), even if it is not (currently) connected to anything at the fan end. You need 4-core.

Kind Regards, John

 

[bernardgreen]

Is there a three core without an earth available? Seems a bodge to have a spare earth flapping about & no room in the fan to finish it in a block.

The "spare" earth reduces the risk of a nail through the flex becoming live. If there is a earth and the nail hits live and earth MCB and/or RCD will trip to remove power.

It is a bodge to NOT have the earth there.

 

[AdamCH]

So would you advise use of 2 + E flex to cable up fittings like mains voltage downlighters with no earth as well then?

 

[JohnW2]

So would you advise use of 2 + E flex to cable up fittings like mains voltage downlighters with no earth as well then?

Exactly - and 'advise' is a little weak, since it's essential.

Kind Regards, John

 

[AdamCH]

Ok

Hadn't thought of it in the context of protecting the cable rather than the device.

Many thanks

 

[JohnW2]

Ok Hadn't thought of it in the context of protecting the cable rather than the device.

It's not only the cable it's protecting - it's also the person who touches the nail after they've put it through the cable. Also, as previously mentioned, someone may subsequently connect something to the end of the cable which does require an 'earth'connection.

Kind Regards, John

 

[DetlefSchmitz]

It's also a requirement for electrical testing of the circuit.

 

[AdamCH]

Hear what you all say about retaining an earth in the cable even if it's not used by the fitting.

Out of interest would a nail through the live that didn't nick the earth trigger the RCD?

 

[RF Lighting]

No.

 

[phatboy]

Out of interest would a nail through the live that didn't nick the earth trigger the RCD?

Not until someone touched the nail