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Topic Title: Testing with electronic dimmers
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Created On: 12 October 2012 07:45 PM
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 12 October 2012 07:45 PM
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We've recently had installed a centralised smart lighting system (Lutron Homeworks)
Each dimmer pack has its power feed protected by an RCD
and each dimmer pack directly feeds 4 lighting circuits

The electrician can't complete the live tests due to the electronics in the dimmers. Recommendations from the manufacturer, and all other electricians I've spoke to is to bridge the dimmer out, complete the tests and note on the certificate this

However the electrician is unwilling to give a certificate to this effect
And is saying that because he cant complete the tests the system should be switched on

Is he being unreasonable ?

I understand that it is accepted practice to bridge out the dimmers and every single other person I have spoke to agrees
 12 October 2012 07:55 PM
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the system should be switched on
I'm guessing you meant to say he's saying shouldn't be switched on?
I say he is being unreasonable, by-passing the dimmers is a perfectly satisfactory way of testing the circuit,

 12 October 2012 08:05 PM
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Hi Mr gadget, must admit I've no experience with these lutron systems, but they are surely no different to installing any type of simple dimmer, if i am reading your post correctly it seems the electrician is saying that he is unable to measure and record earth fault loop impeadance (Zs) reading due to the equipment being connected, but I would say that it is acceptable to obtain and record this figure by calculation using figures that should have been taken at the dead testing stage, prior to connecting the ancilliary equipment ie: Ze+(R1+R2)= Zs

 12 October 2012 08:41 PM
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Last Homeworks system I did all the tests where carried out before the dimmers where fitted as per Lutron instructions. The homeworks panel came with the links fitted, but this was about 10 years ago!
 12 October 2012 08:50 PM
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As per Lutron,

All terminal blocks are shipped with bypass jumpers installed.
After verifying that each circuit is wired correctly, remove the bypass jumpers for system operation.
 12 October 2012 10:34 PM
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When ive tested (I Light system) i treated it as an 'active' consumer unit.
Test all of the outgoing circuits as usual DEAD. Test the incoming feed circuit DEAD and LIVE.
If you want a Zs at the end fittings bridge out the cabling- 1 in to whatever out at a terminal strip.
All tests done- introduce the lighting panel.
You wouldnt test across a consumer unit- just treat this the same.
Call it 'Lutron panel 123' rather than DB123. Garnish with suitable warning stickers along the lines of 'dont test across this panel unless you have the money to buy a new one' or similar

Lack of planning on your part doesn't make it an emergency on mine....

Every man has to know his limitations- Dirty Harry

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