5508D1A Output Protection IEC60669-2-1

First post, I have searched and don't think this is covered on another thread in recent times, I did find a thread from 2005 which might be superceeded. Any advise appreciated.

My preference for installing 5508D1A dimmers was a 1A MCB on the output of the dimmer corcuits, 8A MCB on the dimmer chanel feed and 1A MCB on the control. 16A 30mA MCB/RCD on common feed to cbus panel or RCD's on individual dimmer/relay modules.

Space restrictions make this difficult and I am wondering if the output MCB's are required, Clipsal install information has reference to IEC60669-2-1 requiring the MCB's on the output, but can not find a reference to UK install requirements and that standard, there is a possibility that to be CE compliant the MCB's might be required. If there is not a need through legistation I have to question the need for MCB's.

From a control panel perspective I would prefer to use terminal rail mounted fuse holders and 1A fuses rather than MCB's, particularly as it is not permitted in UK regs to feed circuits in parallel from an MCB as the circuit might be expected to be a ring (how times change!)

Malcolm

 

To shorten the question;

Is protection on the outputs of a 5508D1A dimmer required? Any input appreciated, UK or other areas.

If not is it still a good idea to fit protection on the outputs of a 5508D1A dimmer as a nice to have? Other posts have suggested is it unlikely the protection will be fast enough for a short circuit or close enough for an overload, is this likely to be the case?

Malcolm

 

I would like to comment by saying that I anticipate LED lights and energy saver lights in the near future changing the equation quite markedly.

While it was appropriate to have 1A limits on the outputs, I notice that in the UK people use WAGO inline fuses for some circuits.

But considering that my power demand dropped from 7x50W and needed 2 channels and is now very happy on LED with 70W and one channel (no flickering or issues) I would estimate that 250mA replaceable fuses would be more logical than 1A MCB.

The answer to your question is largely resolved by looking at the loads themselves.

 

The change in load types is a good point and I was thinking along the same lines but came across a Phillips document which suggests otherwise, it applies to Phillips LED's but other LEDs are likely to be similar. (document attached), I doubt the dimmer hardware will alter much as a result for some time 1A or 250mA would not look very different in components.

Reducing the fuse size would only be useful if it improved protection, the cabling will be good for something over 10A and both a 1A or 250mA fuse go in the same holder. 30mA RCD protection covers the personel protection disconnection. Disconnection times should be less for the smaller rating so it could help.

I am happy to install fuses on the outputs on the basis it might help protect the dimmer, I would like to know if a fuse is OK and if regulations require protection and if so just an MCB or is a fuse OK.

If the regulations for installing electronic switches do require protection on the outputs I think the Clipsal information should be much clearer. Insurances companies are always looking to wriggle out of claims and I am sure the newness of LED and CFL technology will mean someone will make a mistake sometime. I am sure most users would think before installing 30 off 7W dimmable LEDs on a chanel (cost alone), but you never know.

I understand the US regulations require dimmer circuits be de-rated if not protected? Something along the lines of max 80% of dimmer rated load, never found a "code" for it though.

I haven't done so in the past but a fuse on the relay module outputs also sounds a reasonable idea, the protection is cheap, improves discrimination, easy isolation for testing.

 

If your electrical design does not exceed the limits of the system in place then any protection in place would serve its function.

Bear in mind that there are also reset-fuses which can last multiple times.

 

Come on you Northerner's.....

Hi Malcolm
We have no such requirements in Australia, so apologies I can't help. That may explain why so many others are quiet on this as well. I have seen other examples from UK based operators on this forum in the past, where they do have a circuit breaker on each output.

Come on you Northerners, help out your country-folk!. Down-under is no good on this one