Immersion heaters - electrician advice needed

[Jacob]

Going to convert my brewery to electric soon but not sure how safe is it?

The plan is to use following:
MT - 2x 2.5kW, HLT - 2x 2.5 kW, pump ...

Can I plug it all to one socket on extension cable?

[Will_D]

NO!

An extension cable plug will have a 13 amp fuse.

A 2.5 kW heater will pull 10 Amps ( Amps = Watt / Voltage approx then is 1000/250 )

If you plug in two on a lead it may work for a short time but everything will get plenty hot.

So you decide to use 4 extension leads?

Next problem is where to plug them. Not into the same room!

The sockets are also protected by fuses or mini-circuit breakers. It then depends on if the sockets are off a radial or spur design.

A true ring main will be fused at 30 amps. Radials to to be at 20 Amps

You need to check how many socket circuits are in your house and what capacity they are.

You should find at least 3: Upstairs, Downstairs and Kitchen

So as a minimum you have 3 sockets.

Hope this helps Jacob. This is why most people get a sparks in to wire the brewery up with a separate fuse board and sockets designed to take the load.

[brenmurph]

good man will, lots to think about there.

Im in the middle of a complete revamp on the house. The electrictian was here before christmas going room to room.

When I suggested what I wanted in the brewery he recomended at least 4mmsq armoured cable ( much higher capacity)  which is equal to about a 6mmsq T&E ( standard cable) and suggested it should be on a 30 amp supply feeding 2 sockets for my two proposed 2.5 kw boilers.

There a lot to consider when loading up a socket with 30 amps ( keeping in mind lads and lassies that a 13 amp socket/ line may take 13- 30 amps(maybe up to 30 amps b4 tripping quickly) for quite a while with just a small overload).  if your cabling is in good nik all should be well as the cable is designed to tak e temperature up to a point, but if you have a very old house with a broken ring circuit then the ring cables could be well overloaded already so dont push it.

If your doin  brewwery pay the 30 quid ( standard labour 1-hr) and get the electrician to assess your supply and make recomendations.
In the meantime use one boilder on a circuit and run an extension cable ( fully unwound) to feed the other boiler from a different part of the house.
And if in dought about your fuseboard safety you can get a portable RCD just to be sure, which I recomend if u dont know that your fuseboard protectors are up to spec and functioning

[Jacob]

That's exactly what I was afraid of. Looks like I wont be able to convert to electric any time soon.
Not going to fix installation in the rented house just to get my keggle working.

[Will_D]

Just use 3 extensions as I suggested and you prolly will be OK.

Worstcase is a 13 amp fuse will blow or a plug/socket may get warm. Also always uncoil an extension lead if you are going to pull max current.

[brenmurph]

! am open to correction on any of this, however my recent experience bringing my centuryold house into the current standards offered me  numerous valuable insights:

The design of a household electrical installation is really aimed at having numerous sockets supplying radios,  mobile chargers and so on so there could be 10 sockets in a room each in theory capable of 13 amps but not several together.

The kitchen would have a seperate high capacity supply for say a cooker, as would a bathroom supplying showers, or a garage extension,  which would be equivalent to what we need in an electric brewery.
Therefore having 2 boilers is just a little more than one electric socket supply is aimed at. I stand corrected but from my research a standard cable (2.5mm T&E) supplying a socket is capable of 30 amps maximum (in free air) while in walls and where many cables run together this reduces/scales right down to 18.5 amps. 18.5 amps CANNOT take two boilers safely. Therefore, 2 scenarios.

Scenario 1. Electrical installation in your house is modern and works properly
The cable will tale the overload safely untill the tripper dis-engages

Scenario 2. The electrical installation is not up to standard, has had improper modifications, has had an original ring circuit damaged or  unringed. The cable will NOT take the overload before the tripper dis-engages and the risult is the well- recognised 'cable fire risk'

My simple recomendation is:

never plug 2 x kettles, 2 x electric boilers  or 2 electric heaters or combination of any into one socket outlet.

For our many brewers using electric kettles this is an issue. Boiling a kettle for a cup of tea is not an issue however having a brew kettle boiling for 90 minutes gives the cables plenty time to overheat


Really the only simple safe solution is 2 x quality extension leads ( fully unwound) taking one from an upstaire socket and one from downstairs).

[Ciderhead]

I'm sure JD will weigh in here.
But get away with running a 2.2Kw on full blast on one socket and the other 2.2Kw on 50-75% depending how cold it is on the same ring main but different sockets.
She can't run the tumble drier but I have 2 fridges a 200W heat bulb and a freezer also running on the same ring at the same time.
Probably just as well all that lots in the garage!

[brenmurph]

@ tube

they also discovered that if for example if the ring broke, the house now has a 30 amp circuit on a 2.5.. cable.... dangerous. so run 2 x boilers will work till the wires go on fire

[brenmurph]

the upgrade on an older house like ,mine is to change the 32 a ring tripper with 20a to ensure safety.

[Jacob]

Ok, here are pics of my fuse box

https://www.dropbox.com/s/7xofro9kl95f67r/IMG_20140102_193554.jpg
https://www.dropbox.com/s/bxm8iru1hlfdwbx/IMG_20140102_193600.jpg

Good, bad?

[brenmurph]

theres only one 32 a which is prob goin to kitchen or shower

ur row of 20a trippers suggests ( but im not an electrician) that your prob not on ring main rather the more modern.

In ur case it looks like ( but im not an electrician) all your sockets are protected with 20a mcb (tripper) which means all should be safe.

If you use 2 x 2.5kw boilers on a double outlet it is likely that it will go for a while and then just trip out.

[Jacob]

Yep, all sockets are on B20 and cooker is on B32.

If you use 2 x 2.5kw boilers on a double outlet it is likely that it will go for a while and then just trip out.

In other words, no good :/

Thanks for the info lads!

[DEMPSEY]

You can always add another 32 to the fuse box and get it spurred to a socket then have a heavy duty cable for plugging into that socket for brew day.

[brenmurph]

thats why as we said earlier the only way is to take power from  sockets that are on different circuits with an extension lead ( fully uncoiled)

you are fine then for 2 x boilers

but u cany use just one double socket for the lot

dont worry ur brewing career is safe

[Jacob]

For the moment I'll stay with gas. Once I'll get my own place will prep all.