Supply To Poultry Shed

[Oxia]

My step father has a very large poultry shed that has been out of action for some years but now he wants to bring it back in to use for chickens. There is no electric supply in there at the moment and so he wants mains fed from the house to this shed.

There will be some sockets just in case we need them, indoor and out door lighting and some form of small heating.

We are going to do all the main cable laying digging out etc and then Im going to ask a friend of mine to come and do the rest and I will help. I have a few questions:

1. At the house end the supply has an earth provided by the supplier, am I allowed to export the earth from the house or do I install a local earth rod next to the shed?

2. Do any of the circuits need to be RCD protected? if so will the standard 30ma apply?

3. If I make the supply TT at the shed end do I buy a 100ma or 300ma RCD to protect the whole supply?

Thanks in advance.

 

[viewer]

Best advice is to get an electrician to do calculations and connections and you do the donkey work. You can dig and put in a conduit (eg100mm drain pipe) from house to chicken shed with a rope pull through and make life easier.
That said, you do need a RCCD and the preferred option for earthing would be not to export the earth but use a rod (making the shed TT). When you say "small heating" what does that mean? Heating the shed, incubators or what? Again a proper calculation is needed for the cables and installation, so I'd stick with the digging and pipe laying and leave the other guy to design and purchase the correct cables and other kit.

 

[Taylortwocities]

I agree, you need an electrician experienced with agricultural installations.

Electricity and livestock do not mix. Unless you want the chickens pre-fried, of course

 

[ericmark]

I would also agree the Fig 705 in regs book gives some rather detailed instructions as to bonding in a cattle shed but I am unsure if this would apply to smaller animals specially with two legs not four.

Section 705 deals with agriculture and horticultural premises

Sockets up to 32A need 30ma and over that 100ma and all circuits 300ma.

To use a TN-C-S supply needs a metal grid laid (705.415.2.1)

Cables need to be buried at 1m depth in some cases.

Electrolytic effects have to be considered.

For standard 13A sockets there is a 20A limit not the normal ring.

 

[ban-all-sheds]

My step father has a very large poultry shed that has been out of action for some years but now he wants to bring it back in to use for chickens.

Free range?

 

[Taylortwocities]

The chickens, or the father in law?

 

[ericmark]

1. At the house end the supply has an earth provided by the supplier, am I allowed to export the earth from the house or do I install a local earth rod next to the shed?

You have not said what the supply type is? TN or TT and if TN is it TN-S or TN-C-S however as to a local earth rod next to the shed, sorry it will need a lot more than that. Likely either a series of rods or connect the re-bar used to build the building in the first place. I know today we build in earthing cables before the concrete is poured but not sure what would be done where the building already exists.

2. Do any of the circuits need to be RCD protected? if so will the standard 30ma apply?

The regulations state where 30ma, 100ma, and 300ma RCD's are required and also makes reference to use of S type delayed types. With 13A sockets it will need 30ma. Lights and heaters would need 300ma or less and sockets over 32A will need 100ma.

3. If I make the supply TT at the shed end do I buy a 100ma or 300ma RCD to protect the whole supply?

I would use a S type 300ma but you may find that 300ma are more expensive that 100ma S type so there may be a case for 100ma. What one has to be careful with is anything which is for live support and you may not be allowed to use a single RCD to protect all but may need to have a dedicated RCD for example heating or ventilation.

At home we will just select a bit of pipe for ducting to make it easy but in your case even that is not so easy needs to stand 5 Joules and also there are strict rules as to earthing/bonding where detailed plans are required so the units can be regularly tested one of the worries is electrolysis eating away earth rods. As to eating away there is also the rodent problem this is worse than one first thinks. I have had the SWA of a cable fail where rodents have eaten the outer plastic allowing electrolysis to do the rest.

I think the problem is the jobs worth inspector. We can do a risk assessment and decide we don't really need all the stuff quoted in the book. But then some inspector decides he will not accept it. I have had it where an inspector was even measuring the holes in a guard mesh to ensure they were under 12.5 mm. What you have to consider is who will inspect and how strict will they be. Existing business will have some leeway when an inspector finds something he does not like with often time granted to correct. As something new that's not the case you only have to look at all the extractor fans fitted in new houses and silly lamp fittings which will not take tungsten bulbs.

If I was asked to do the job I would quote a silly high price as I would not want the hassle. Which is why you really need to go to some one local who does the farm electrics all the time. He will know all the inspectors and know what he can or can't get away with.

 

[Oxia]

Just spoke to my friend who is a electrician, he says 10mm 2 core XLPA SWA over the 70m distance to provide a 30A supply. Local earth rods to create a TT system. In to the shed direct to a 30A switch fuse, from there to a consumer unit containing a 300ma RCD main switch and RCBOs on each out going way (to stop us having lots of equipment on the wall)

From that it will feed some lights etc.

Does this sound about right as it seems a bit over kill to me... this is NOT an industrial operation!

Thanks

 

[JohnW2]

... In to the shed direct to a 30A switch fuse, from there to a consumer unit containing a 300ma RCD main switch and RCBOs on each out going way (to stop us having lots of equipment on the wall)

Are you sure that you got that the right way around? Having a 30A switch fuse at the shed end, immediately before the CU, does not seem to make much sense. I would have thought that the switch fuse ought to be at the other ('house') end of the SWA.

Kindest Regards, John

 

[Oxia]

... In to the shed direct to a 30A switch fuse, from there to a consumer unit containing a 300ma RCD main switch and RCBOs on each out going way (to stop us having lots of equipment on the wall)

Are you sure that you got that the right way around? Having a 30A switch fuse at the shed end, immediately before the CU, does not seem to make much sense. I would have thought that the switch fuse ought to be at the other ('house') end of the SWA.

Kindest Regards, John

Im not sure, may have got it wrong. Does it have to be a switch fuse when I have a spare MCB way?

 

[ban-all-sheds]

Much better to have it on a switchfuse than from the house CU.

But the 300mA RCD in a CU with RCBOs is utterly pointless.

 

[RF Lighting]

Where abouts in Yorkshire are you?

Are you going to be farming chickens or hens?

You don't mention any provision for waste management. I'm assuming you'll have large extraction fans in the shed to extract all the ammonia, and a conveyor or auger for the poo?

Is there an automatic feeder too? What about an egg conveyor / packaging plant?

Whilst parts of section 705 will apply to this installation, things like the earthed grid in a concrete floor are not necessary. Generally the birds will be on a suspended metal grid floor which allows all the waste to drop through to some sort of removal system below.

As has already been said, you need an electrician experienced in farm installations to properly design this job. Don't assume that every electrician is capable of carrying out this work.

 

[Iggifer]

RF - I think you are imagining this on a far more commercial scale than I think perhaps it is.

From the sounds of it, it's more of a ramshackle shed than a complex operation. I imagine waste management will be manual, eggs collected by hand and the chickens just on the floor.

I could be wrong

 

[JohnW2]

RF - I think you are imagining this on a far more commercial scale than I think perhaps it is. From the sounds of it, it's more of a ramshackle shed than a complex operation. I imagine waste management will be manual, eggs collected by hand and the chickens just on the floor. I could be wrong

I was wondering the same - but, in terms of scale, he did describe it as a 'very large' poultry shed.

Kind Regards, John

 

[RF Lighting]

To me a very large poultry shed would have all I mentioned. I do work at a hen shed with three or four thousand birds, and they don't consider them selves to be a particularly large farm.

Maybe the op can let us know how large the large shed really is?