Tumble Dryer in the Garage

[masamune]

I appreciate the subject has been discussed to death but perhaps every case has to be examined on its own merit. So before spending for a failure project, it may help discuss a few facts first.

My place has no space for a tumble dryer and drying clothes in the house has become a bit of an issue for obvious reasons. We want to place a dryer in the garage, the only possible location. The garage is not attached to the house.

I am looking at buying a condensing tumble dryer, I will use one I've seen online as our test case, which says that on full load for cottons it consumes 4.2KW

At the moment the garage is supplied by a radial 2.5mm T&E with the following configuration. The CU has dual RCD and because the tails were extended to move the entire CU from under the stairs to the hallway, there is a connection block under the stairs where the old CU used to be.

The circuit has 20A MCB, the cable runs up to the block (about 4m length) and from there it goes through to the outside wall, through a conduit of about 10 meters long to a dual gang IP65 socket in the garage. There is a fused spur under the stairs and another fused spur just before the socket (these are 13A I believe).

The questions,

1. I have heard of people putting dryers in the garage, how does that work with freezing temperatures during the winter? i) can the dryer get damage from frost ii) is it possible it will seriously underperform in low ambient temperature i.e 1oC

2. Assuming (1) above is not a major issue, if the dryer wattage is around 4~4.2kW on full load*, can it be supported by the 2.5mm cable with a 20A MCB at this length/voltage drop?

*Considering that the dryer may need to run for 2 hours continuously for a cycle based on one of the programmes.

If not, what would be the best cable to run to the garage for that purpose.

Thanks

 

[deadshort]

If the dryer is 4.2kw you require 16a minimum the 2.5mm will be OK but you need to remove the FCU at both ends and have the house end connected to your CU on it's own breaker rated at 16/20a

Regards,

DS

 

[Adam_151]

Are you sure that this is a 4.2kw dryer (note, if it is supplied with a plug attached... it will not be).

 

[big-all]

i would suspect its nearer 2kw and the drying time maybe 100 mins
"on full load for cottons it consumes 4.2KW"

 

[sparkwright]

Send us a link for the tble dryer in question, so we can be sure of what we're talking about.

 

[flameport]

It won't be a 4.2kW appliance. Like ovens and much else, 4.2kWh is the electricity used for a particular cycle in some laboratory test which does not represent typical use.
The actual rating probably isn't mentioned as manufacturers apparently consider this information irrelevant.

If it's a condensing one and you leave it full of water, the water could freeze and crack the plastic container it is held in.
Other than that, the lower ambient temperature will not be a problem.

You do not need a condensing model - they are only used where it is impossible to vent the thing to the outside air.
Buy a standard non-condensing one and fit the vent through the wall.

 

[eveares]

You say it's a condensing tumble dryer, does that mean it has a heat pump in it?; is it a 4.2Kw electrical load, or 4.2Kw heat output? (Just as AC units have a higher heating/cooling Kw rating that their electrical Kw ratting.

Also, you say it consumes 4.2kW; that was not 4.2kWh by any chance, what is the amount of energy it uses per cycle/program. (A kWh = The amount of energy that a 1kW load applied for one hour uses.)

Assuming it's a 4.2Kw electrical load, it is going to be unsustainable to be plugged in via a 13A plug or wired into a fused spur and is going to need a 20A DP Switch and be protected by the 20A MCB. If the 20A MCB turns out to not be protected by the RCD (unlikely being that you have a Dual RCD split load board), then the 20A MCB should be replaced with a 20A RCBO.

2.5mm² will likely be ok from a voltage drop perspective, but to be certain I would need to know the total cable length between the main CU and where the tumble dryer is to be installed along with the instillation method of the cable.

Regarding your first question about the freezing temperatures, i'm afraid I can't help you.

Regards: Elliott

 

[stillp]

If you use a non-condensing dryer, most of the heat it generates will have to be extracted to the outside. On the other hand, if you use a condensing type, the humidity in the garage will increase, causing condensation on any cold metal objects, but it will get warm in there.

 

[JohnW2]

I am looking at buying a condensing tumble dryer, I will use one I've seen online as our test case, which says that on full load for cottons it consumes 4.2KW

Unless it's a non-domestic model and/or intended for markets other than the UK, as has been said it's extremely unlikely that it requires 4.2kW.

Does it come (as virtually all UK dyers do) with a fitted 13A UK plug. If so, its power requirement cannot be greater than 3kW.

Also, as has been said, there's absolutely no point (and some potential downsides) of having a condensing dryer in an 'outhouse'.

Kind Regards, John

 

[EFLImpudence]

It's not going to be 4.2kW.

That would be a silly rating for a manufacturer to make.

 

[masamune]

Apologies, just realised my silly mistake, it is indeed 4.2kWh! It couldn't possibly be 4.2kW even an oven never uses as many elements in one go. It does come with a fitted 13A plug not a flex, it was a Bosch model I was looking at. I misread the spec sheet and have never owned a dryer before, hence the stupid post...(I was actually wondering how the heck it can be 4kW)

edit: total cable length is about 15~20 meters long.

As well pointed out a condensing dryer may cause more problems in the garage to the structure and things stored in there, so I should look at vented units. Although I was not planning on leaving the tray full of water - for obvious reasons

 

[Taylortwocities]

The tray of water is not the real reason for concern.

Maybe you should have a read of this guidance.
http://www.ukwhitegoods.co.uk/help/.../3022-tumble-dryers-installation-requirements

 

[Tipper]

Our condensing drier does not have a heat pump neither does it exhaust any humidity into the room where it is located. It does warm up that room.
It has two separate air circuits. Firstly circulating warmed air through the drum to dry the clothes and secondly an external air circuit through a heat exchanger that cools the warm wet air and so condenses out the water in it and collects it in a container. It doesn't like being shut in a small room either as the cooling airflow warms up and it doesn't condense properly. It's fast too and runs for far less time than I expected it to.

Of more importance in my mind is that the heating elements in a conventional drier could be in contact with petrol vapour from any petrol split or leaking into the garage....

 

[JohnW2]

Of more importance in my mind is that the heating elements in a conventional drier could be in contact with petrol vapour from any petrol split or leaking into the garage....

Why not similarly with a condensing dryer?

Kind Regards, John

 

[flameport]

petrol vapour from any petrol split or leaking into the garage....

Approximately 100% of garages are not used for vehicles, and have never had a vehicle in them in the entirety of their existence.
A fair number are too small to actually get a car into.