Dad is concerned with all the wet weather, that if the garage gets damp, it's going to take the electrics out, which further up the line has a chest freezer on it.
He picked up a garage unit from Screwfix, and asked me how to wire it. I **WAS** quite confident I knew (see linked pic).
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Problem is (and what's thrown me), is the spare pin in the bus-bar. What's the point of the insulation shroud, if there is a pin to get a shock from?
Am I missing something obvious, or doubting my own ability? (apologies for the old-skool wiring colors)
Me neither (Firefox 26 in XP SP3) but it downloads then opens OK so I suspect it's Google not playing nicely with what they see as the hoi polloi
I think the problem is that the CU is not full but the busbar has been left uncut (or not cut enough). Best though for the OP *not* to cut it until someone better than me says so - the more so as the shield doesn't seem to be covering the busbar as well as I'd expect!
It there me, as everything shown was supplied but not fitted. Seemed odd to supply a bus bar that supported more mcb than they supplied, so much that it made me question my sanity
It threw me, as everything shown was supplied but not fitted. Seemed odd to supply a bus bar that supported more mcb than they supplied, so much that it made me question my sanity
The CU has provision for three MCBs in total, and is pre-poulated with two. The front cover should have a blanking plate to stop joe public sticking his finger in there once the lid is on. If however you are working on it live and open, then you will need to take care not to go prodding that bit!
(if you are sure you will never need the extra way then you can trim the bus bar vertically to the left of the next finger along).
I know it's sold by SF as a garage CU, but it's far from ideal. Trouble is that both circuits are off a single RCD. If a faulty power tool trips the RCD, you lose the lighting circuit too - and potentially dangerous machinery may still be spinning in the dark.
That is for another MCB. When the top cover is fitted there should be a blanking piece to fill the gap where the third MCB could/would be fitted. For a few quid you could bung in a third MCB which would cover the offending tab
Don't forget that this is a view only a 'qualified electrician' should have access to. Once the cover (with CB blanking plate) has been refitted, it's all perfectly fine.
The 'qualified electrician' will know to use the 40A 2 pole isolator switch to disconnect that three pronged busbar before attempting to install a third CB (I'd expect the cover is designed to require the isolator switch to be in the off position before it can be removed anyway -BICBW in _this_ case).
The experienced 'qualified electrician' will also know to verify that the isolator switch _has_ actually disconnected the live by using his trusted meter or neon screwdriver (after verifying that his chosen instrument of test is still capable of indicating the presence of mains voltage before switching off).
It should really come as no surprise that removing the safety cover off any consumer unit _will_ reveal exposed and accessable live metalwork. Admittedly, in this case, that clipped on bit of plastic seems a little pointless considering the approved handling practice by the 'qualified electrician' when working on such kit is supposed to prevent such 'accidental contact' as seems to be its purpose.
That's why mine is from the main CU's 100mA side, then the lights direct from a 6A MCB and the sockets from a 16A MCB on a 30mA RCD. It's never happened, but if a socket trips the lights should stay on.
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