MCB questions

[Hogarth]

Although most of the electrics in my house is prehistoric — all fuse wire and cobwebs — I thought I'd get modern in the brewery and install some MCBs and RCDs. Can some kind sparky type help me out with these questions?

1) For a brewery running two kettle elements simultaneously, is a b-type 32-amp the right sort of MCB to use?
2) Instead of doing that, is there any advantage in using, say, two 16-amp MCBs, one per element? I can do this quite easily on my set-up, as there are two distinct circuits in the control panel.
3) Seeing as I use the brewery fairly irregularly, is it okay to use the MCBs as main switches too? Or is that naughty?

Cheers!

[themadhippy]

2 mcb' will give you fault discrimination and allow you to use a smaller cable to feed each element,if you go with single 32 a fault fault on 1 elemt will take out the power to both and youll need to use 32a cable for everything.as for mcbs as a switch, yep perfectly ok



Another thought how about using 2 16A rcbo's

[Buckie Brewer]

I bought one of these and added another 16A MCB. I ran two sockets on each 16a MCB and the shed light on the 6a. The plan was to have a two element boiler with the elements each plugged into a separate ring and just use normal 13 amp kettle leads. I then bought a Grainfather instead but the wiring/setup is the same.

[JamesF]

I'd be tempted to run a pair of radials that would allow you to upgrade to more powerful elements in the future without changing the cabling. Of course if the cabling is going to be easy to replace that might not be an issue.

I an not an electrician though.

James

[Jocky]

Get sparky in to fit a new consumer board to get rid of the nasty and not particularly safe wired fuses. He can then run a dedicated brewing circuit for you as you need.

Right now you can install a 32amp MCB, but unless that circuit is rated (and ideally tested for) 32 amp you're in danger of overloading the circuit.

[jaroporter]

only problem i see with using MCBs as switches is if there's any chance another person might come along and flip them up when you're not in brewery

[GAZ9053]

I would have a new DB fitted in the house with RCD protection. New dedicated circuit to brewery. Then have separate circuits fitted with local isolation not using mcb as a switch. That way everything is RCD protected including brewery feed cable.

[BenB]

Having a separate lighting circuit with its own mcb is certainly an idea. Or having a single emergency bulkhead light (15 quid from CPC). Otherwise if an element goes you'll be in a pitch black shed with boiling liquid just a stumble away..

[themadhippy]

Having a separate lighting circuit with its own mcb is certainly an idea

indeed,although if the rcd goes (more likely) youve still lost the light, a switched fuse spur off the ring gives you the overload protection for the lighting circuit and doubles up as an on off switch,also frees up a way in the fuse board,

[jaroporter]

guess you'd need to know if the intention is to add protection to existing circuits on the board, add protected circuits to the board, feed an RCD protected brewery unit, upgrade to a new board or rewire the whole damned house.. :p

[Hogarth]

Thanks for these useful replies, guys. I popped up to Screwfix and bought one of their little garage consumer units, on sale for £19 — which is the same price as the RCD alone. I'll add a couple of 16A MCBs, one for each of the brewery circuits. The brewery's in the house so no lighting circuit is needed, and the unit will go inside a cupboard so there's little chance of anyone flipping a switch.

Yeah, I know I should get the whole house overhauled but that's for another day. I've been running the brewery off the kitchen circuit for years without any noticeable accidents, so I'll carry on like that for the nonce.