Todays work nightmare

[ARW]

I was called out last week to look at one on these that was not working.

installation manual here

A brand new installation by our firm a month ago but not commissioned as there was no power to the circuit. The other firm of electricians that were doing the powering up said that it did not work when they applied power.

The left hand gang is for the already second fixed spotlights and the right hand gang powers a second fixed 5A socket that will power a table lamp when the owner of the property moves in.

So last week when problem solving I reversed the two switched live outputs and the spots worked fine using the RH gang. My conclusion was that the LH gang was fault:-(.

New switch arrived today and my mate went to replace it. He had exactly the same problem as me. Not believing that two switches would fail the same way he phoned their tech department.

Took them over an hour to tell my mate that "with no minimum load on the RH gang of any of our multi gang switches then the switch will not work at all"

So why not put that info into the installation manual you f****ng wankers.

[michael adams]

I'm not an electrician so maybe this is bollocks. But does

1. [...]

Important things to consider . In a multigang dimmer, to be able to operate any gang, mains electricity must always be connected to all of the dimmer terminals.

have any bearing on the matter in hand ?

michael adams

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[michael adams]

michael adams

...

[ARW]

Do you think the instructions should say "the right hand gang needs a minimum load to make the other gangs work?".

BTW if the RH gang only feeds one lamp and that lamp blows then the dimmer will stop working":-)

[michael adams]

Well in fact it does say this -

Troubleshooting (first page)

Problem: The dimmer will not operate the light and the LEDs on the dimmer do not light up. Solution: First, check that there is power to the dimmer. Make sure that the connected lamps are functioning correctly; the dimmer switch will not run unless it has a functioning lamp(s) to complete the circuit.

In fact it seems to be saying that you need a lamp on both gangs to work at all. When in fact it seems you only need a lamp on the RH.

However that shouldn't be in the troubleshooting page.

It should be in the basic specifications so people know about this limitation before deciding whether to buy the things or not.

Not having to find out afterwards by scouring the instructions to discover why they're not working. In fact its maybe just as well you've found this out, rather than having both gangs loaded all the time as you'll be able to forewarn the owners. While maybe supplying them with a cheap table lamp in the meantime Assuming it was them who specified those particular switches

The pictures in the instructions are nice though.

And you do get the different coloured flashing lights.

michael adams

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[Graham.]

"This product is not fit for purpose, see RMA details on Pg12".

[Robin]

Which I would have taken to mean only that you can't expect the

*particular* dimmer you are playing with to operate unless there is a load on *that* dimmer.

It does not go on to say "and the dimmer switch on the left won't work even if it has a load connected unless there is also a load connected to the one on the right".

Err...and presumably also if anyone has the audacity to turn off the table lamp with an old fashioned switch thingy what makes it an open circuit.

Pity the IET has AFAIK no "oops awards.

[michael adams]

Maybe I'm missing something here, but why would anyone expect a dimmer to work on a lamp that isn't working ?

See above.

michael adams

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[John Rumm]

You might expect one switch to work it its lamp, even if the other switch has a dead lamp.

The problem with most of these "clever" switches that contain electronics, they need some way to be powered. That's tricky on most light switch locations since there is no readily available neutral. Often they draw a small current through the lamp.

Its a dodgy practice to start with, but only works at all when the lamp is a permanently connected one that can't be switched locally. They are also doubtful with low energy lamps.

[dennis]

All two terminal inline dimmers need a lamp in to work (unless they have a battery).

The lamp is the only path to neutral.

There will be a minimum load specified to get enough current to flow to power the electronics, zero is too low.

[Muddymike]

The user should also be warned.

If I had one of these and all lights fed from it stopped working I would think I had a more serious fault then just a simple blown bulb.

Mike

[Reentrant]

They mentioned on a recent "This Old House" that it has been a code requirement in the USA for several years to provide full three-wire supply (live, neutral, earth) to all switch sockets, for exactly this reason.

(And yet they still allow wire-nut connectors).

[ARW]

When did you last see them on sale in the UK?

[polygonum]

For some values of "in the UK", today!

[ARW]

Only £92.52 for 100?

Try