What size is the swa and what size is the main fuse ?
And again...
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You do have a good point. My house is on a 60A fuse and I have a few times said what happens when the DNO come into a house and replace the fuse?
In an ideal world the person changing the fuse should ensure all after the fuse will take the extra load.
This raises a further question should one guard against some one in the future breaking the rules?
My RCD is rated at 63A so if my incoming fuse was to blow it should be replaced with a 60A.
But I have seen many consumer unit changes where 63A RCD's are fitted but it has a 100A incoming fuse. I blame electricians being lazy and since the consumer unit comes fitted with a 63A RCD they continue with that size. With a 32A and couple of 16A MCB's clearly 63A can't be exceeded anyway. But I have seen a 45A (Shower) 32A (Ring) 16A (Garage) 6A (Lights) etc all connected to a single RCD rated at 63A and the electrician was adamant that diversity allowed this to be done. Again he seemed not to understand the difference between a RCD and a MCB.
Yes I will admit it is unlikely it will become overloaded but the same could be said for the RCD in the picture. To use two 32A MCB's on 63A supply is I suppose 1A overload but I would ignore that. But at what point should we ignore the potential for something to be overloaded?
Interesting question. However, the main fuse will presumably be at least 60A and that SWA doesn't look to me to be 10mm² or more. Furthermore, the feeds from Henleys to RCD look like only 10mm², which would be a problem if the main fuse was 80A or larger. In any event, reliance on the cutout fuse for protection of cables is surely not 'good practice' and I imagine may well represent a problem for the DNO (if they find out about it).
Kind Regards, John.
But if the subsequent fuse protecting the SWA was also 60A, then nothing has changed. No discrimination.
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Perhaps they don't want to take any responsibility for protection of the customer's installation, seeing as the main fuse is there to protect their network and is not part of the installation.
One would imagine that would be their view. However, provided they didn't advocate it (which I'm sure they don't!), I don't think they would acquire any responsibility for protecting a customer's installation if that customer chose not to install any protection of their own. Nor can one really explain it in terms of 'convenience' (for the DNO), since a switchfuse which offered little discrimination from the DNO's fuse (with which they seem perfectly happy) would mean that the DNO's fuse would be quite likely to operate under fault/overload conditions.
Kind Regards, John.
RF Lighting, I know that this was posted as an example of something done incorrectly. But can I ask, is this a example of where the meter tails have been split. Is the black box on the wooden board below the CU a Henley Block?
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Note: Other makes of service block are available.
For those interested, the SWA was 2.5mm² 4 core with 2 unused cores for some reason.
Not sure on the main fuse size but I'd imagine 80/100A
Not sure on the main fuse size but I'd imagine 80/100A
Some may have been tempted to double them up to simulate 5mm² 2-core
Kind Regards, John
I'd have at least tied them to earth. You can't have too big an earth
Agreed. I should have added that to what I said.I'd have at least tied them to earth. You can't have too big an earth
Kind Regards, John.
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