Heated Mirrors and dimming..

[crunchynut]

Hi All.

I am installing a heated mirror panel in a small ensuite. I was planning on connecting it in parallel with two downlights so it is not constantly left on due to forgetfulness.

I was planning on getting a pull-cord dimmer, and I am wondering if the panel would be OK with the variable current due to the dimmer??

I have looked at the elec spec provided with the panel, and could find nothing to tell me.

These panels are based on the same principal as U.F.Heating, and obviously there temperature, and therefore current(?) can be variable.

Also, are pull-cord dimmers worthwhile? Easily broken? any good? ETC!!

Thanks

 

[Spark123]

It's worth waiting for a 2nd opinion as I am not 100% familiar with what you intend to do but here goes;
I wouldn't be tempted to wire the heater through the dimmer, what current rating is the heater? Do pullcord dimmers not have a normal switch on them as well for wiring timed fans, would it be better wiring it to that? If the unit is in zone 1,2,3 it needs its circuit added to the supplementary equipotential bonding although I'd expect a light circuit to already be connected. The heater needs to have a double pole switch installed for isolation purposes, zones apply to isolator location. As this is a special location it needs to be notified to LABC under part P of the building regs.

 

[crunchynut]

Yeah, I think I will attach it to a separate 'pneumatic' timed switch (like you get in shared passage's of flats). The panels capacity is 65W. So I make its current to be 0.3 amps. (I used P over I times V for this!). But is current the same as current rating though.

I dont know whether these dimmers have a normal switch also.

The panel is double insulated and IP34. There is no earth cpc on the panels outgoing wire. And the instructions state it should be wired through the lighting system using a MCB/RCCD as applicable. So will I need a DP switch aswell as a MCB?

Also, where in the circuit do I connect it to earth?

Thanks

 

[Spark123]

If it is double insulated the unit does not require earthed, the CPC however is required to be made available and supplementary bonded in case it is changed for a class 1 fixture in the future. If it is fed from the lighting circuit which is already supp. bonded then this requirement is already fulfilled. An RCD will be required if the manufacturer has specified one.

Some bedtime reading:
http://www.niceic.org.uk/downloads/NL139supp.pdf
http://www.niceic.org.uk/downloads/Earthing Bonding guide.pdf
http://www.iee.org/Publish/WireRegs/EarthingPlasticPipes.pdf
Ban-all-Sheds part p summary 04/06
Guidance to approved document P

 

[crunchynut]

Thanks again Spark.

I have looked briefly through the links. Looks quite interesting.