Another wiring a shed question

ocj

Hi there,

I know there have been a few questions here before on wiring a shed but I can't find what I'm after.
Basically I've built a Shed at the back of the house with steel sheeting and now need to wire the shed. I can get access to the consumer unit at the house but wanted to use earthed cabling on the lights and sockets as the shed is steel. You know "to be sure, to be sure"
What size cabling should I use for the lights and sockets and where's the best place to buy this around the Dublin area?

I'll be using another consumer box in the shed with a 10 MCB for the lights and 20 mcb for the sockets.
Any help appreciated.
Cheers
OCJ

M cebee

you should hire an electrician

you may be able to supply materials and get a cheap labour only quote

JustRoss23

Agree with Mcebee that's a job for an electrician.

paddy147

yep..job for a sparks.


You could supply the materials and then just pay for the labour.

JustRoss23

or an apprentice with a lot of knowledge and that knows the score a good apprentice is hard to find though aham aham;)

paddy147

ocj wrote: »

Hi there,

I know there have been a few questions here before on wiring a shed but I can't find what I'm after.
Basically I've built a Shed at the back of the house with steel sheeting and now need to wire the shed. I can get access to the consumer unit at the house but wanted to use earthed cabling on the lights and sockets as the shed is steel. You know "to be sure, to be sure"
What size cabling should I use for the lights and sockets and where's the best place to buy this around the Dublin area?

I'll be using another consumer box in the shed with a 10 MCB for the lights and 20 mcb for the sockets.
Any help appreciated.
Cheers
OCJ

Lights.......1.5 nymj

Sockets.....2.5nymj

Any electrical wholesalers will stock it by the meter.


Consumer unit for shed needs to be IP RATED

But as all have said above...get a sparks to hook it all up.

paddy147

JustRoss23 wrote: »

or an apprentice with a lot of knowledge and that knows the score a good apprentice is hard to find though aham aham;)

Can you certify the work and are you fully insured????????;)

JustRoss23

no sadly not:( i always wondered why is that? an apprentice that has his 7 phases done (me) but just making up the short months to make the 4 years not allowed to do the course to certify the work? like in theory i have completed all the phases:(

Stoner

if the shed is waterproof new and clean then a standard consumer unit would be fine.
Any cable you use for lighting and sockets will have an earth cable in it regardless of your shed being steel or not, no need to be sure to be sure even if it was a plastic shed it wold need the correct earthing cabling.

To add extra earthing and equi potential bonding protection to your shed try for steel back boxes on the sockets and light switches, these should be fly earthed if you fit them to the shed using self tapping screws you will be earthing earthing the shed at these points, Depending on the length of the run to the shed you could be talking anywhere from 4.sq 6.sq or 10.sq cabling. bond link and steel tables or work tops you intend to use. There are plenty of threads here.

the best possible saving for you IMHO would be to run the main cable in yourself and get an electrician to do the hook up, if you have a route to your shed that you can clip a cable to and the shed is not far away an NYMJ cable will do just fine, small spans over a doorway can be jumbed with a straight bit of steel conduit with a 20mm compression gland at either end. Most people would like to see a SWA cable here minimum 6sq it will be more expensive but a better job. It does sound like you need a sparks though, best of luck

paddy147

Stoner wrote: »

if the shed is waterproof new and clean then a standard consumer unit would be fine.
Any cable you use for lighting and sockets will have an earth cable in it regardless of your shed being steel or not, no need to be sure to be sure even if it was a plastic shed it wold need the correct earthing cabling.

To add extra earthing and equi potential bonding protection to your shed try for steel back boxes on the sockets and light switches, these should be fly earthed if you fit them to the shed using self tapping screws you will be earthing earthing the shed at these points, Depending on the length of the run to the shed you could be talking anywhere from 4.sq 6.sq or 10.sq cabling. bond link and steel tables or work tops you intend to use.There are plenty of threads here.
the best possible saving for you IMHO would be to run the main cable in yourself and get an electrician to do the hook up, if you have a route to your shed that you can clip a cable to and the shed is not far away an NYMJ cable will do just fine, small spans over a doorway can be jumbed with a straight bit of steel conduit with a 20mm compression gland at either end. Most people would like to see a SWA cable here minimum 6sq it will be more expensive but a better job. It does sound like you need a sparks though, best of luck

Exactly what I did with my garage.:)

10 square SWA ran underground in a 600mm deep trench from house down through the back garden to garage.
2.5nymj for double sockets and 1.5nymj for lights.
All double sockets are metal conduit/metal back boxes/metal faceplates and are installed at 1.2 meter height,to allow for work bench instalation and easy use of power tools and equipement

Saved a good bit of money too,by going down the labour only route.

ted1

Paddy there's a fine line between a shed and a mews!!!

.G.

It should be in red ESB grade ducting with yellow warning tape above it if your going underground.

paddy147

ted1 wrote: »

Paddy there's a fine line between a shed and a mews!!!

:pac::D

paddy147

superg wrote: »

It should be in red ESB grade ducting with yellow warning tape above it if your going underground.

It is indeed......along with 5 inches of horticultural grit too......for any future digging down that deep.:)

cast_iron

JustRoss23 wrote: »

no sadly not:( i always wondered why is that? an apprentice that has his 7 phases done (me) but just making up the short months to make the 4 years not allowed to do the course to certify the work? like in theory i have completed all the phases:(

Well not only do you have to be fully qualified, you also need to have insurance and be registered with one of the certifying bodies - so they can periodically check your work.

I can't imagine too many RECs issuing certs for the job described above. A ridiculous waste of time and money, imo. And I certainly can't imagine any customer asking for it in any case. I also doubt there would be a single consequence if an issue arose and it was found not to have been certified.

paddy147

cast_iron wrote: »

Well not only do you have to be fully qualified, you also need to have insurance and be registered with one of the certifying bodies - so they can periodically check your work.

I can't imagine too many RECs issuing certs for the job described above. A ridiculous waste of time and money, imo. And I certainly can't imagine any customer asking for it in any case. I also doubt there would be a single consequence if an issue arose and it was found not to have been certified.

TV ad on RTE at the moment saying about "safe electric".....;):)

JustRoss23

jeezus paddy give an apprentice a break

deandean

A question I am not sure of: do your run the house earth wire to the shed or do you just run a live & neutral and have a separate earth rod for the shed consumer board?

meercat

deandean wrote: »

A question I am not sure of: do your run the house earth wire to the shed or do you just run a live & neutral and have a separate earth rod for the shed consumer board?

:eek:

JustRoss23

It didn't even deserve a reply. please whatever you do. DO NOT WIRE THAT SHED from your comment you are obvious not up to the job i don't mean to insult you.

2011

deandean wrote: »

do your run the house earth wire to the shed or do you just run a live & neutral and have a separate earth rod for the shed consumer board?

Normally a 3 core cable would supply a sub-distribution board in the shed. This cable would contain the phase, neutral and earth conductors. The earth (or CPC) would be connected to the main earth bar in the distribution board on the supply end and at the earth bar in the new board at the other end. Normally an earth electrode would not be installed at the shed.

I think that it is important that people regardless of experience or qualifications should be able to ask questions. That what this forum is about and how we can learn from each other.

2011

cast_iron wrote: »

I also doubt there would be a single consequence if an issue arose and it was found not to have been certified.

.....unless somebody is seriously injured, killed or there is a large amount of damage caused by a fire. But sure that never happens.

paddy147

2011 wrote: »

.....unless somebody is seriously injured, killed or there is a large amount of damage caused by a fire. But sure that never happens.

Same thing with insurance companies voiding insurance policies because householders didnt use RGI certified people for the gas/plumbing work.


In several of todays newspapers.;)

M cebee

deandean wrote: »

A question I am not sure of: do your run the house earth wire to the shed or do you just run a live & neutral and have a separate earth rod for the shed consumer board?

they actually do that in a lot of uk outbuildings

run a 2-core out,separate rod and convert to TT(maybe you saw that somewhere?)

but you should hire a sparkie labour only to avoid hassle and get it done right

2011

M cebee wrote: »

they actually do that in a lot of uk outbuildings

run a 2-core out,separate rod and convert to TT(maybe you saw that somewhere?)

I have never seen this, then again I have not worked in the UK.

My concern would be that the earth fault loop impedance would be too high if this was method was used. A high EFLI would mean that the MCB or fuse would not operate within the specified time.

Bruthal

2011 wrote: »

I have never seen this, then again I have not worked in the UK.

My concern would be that the earth fault loop impedance would be too high if this was method was used. A high EFLI would mean that the MCB or fuse would not operate within the specified time.

Main RCDs are used to cover that.

2011

Bruthal wrote: »

Main RCDs are used to cover that.

I don't see the advantage.

RCDs are a great invention, but they have been known to suffer from "striction".
They take up more space and still require a fuse or MCB.
The main RCD would be 50 or 100 mA trip?

Bruthal

2011 wrote: »

I don't see the advantage.

RCDs are a great invention, but they have been known to suffer from "striction".
They take up more space and still require a fuse or MCB.
The main RCD would be 50 or 100 mA trip?

Its not to do with advantages as such, just a different system in use elsewhere. TT systems have advantages too. A TT system cant be guaranteed to operate MCB`s and/or fuses though, even with multiple earth rods.

So a 100ma RCD or something around that, probably with a delay for discrimination would be used to provide earth fault tripping.

But that was not a suggestion for use here. It was m cebee suggesting that the poster asking about a separate earth rod out at the shed, may have come across such a setup from reading about tt systems, which is a good point.

A separate earth rod would not be used on a neutralised setup anyway.

2011

Bruthal wrote: »

Its not to do with advantages as such, just a different system in use elsewhere. TT systems have advantages too. A TT system cant be guaranteed to operate MCB`s and/or fuses though, even with multiple earth rods.

Part of the reason that I am not a fan of them.

But that was not a suggestion for use here.

+1

Stoner

I agree with 2011 here, we have to remember the DIY element on this forum. if there is something someone can do properly then we can advise on that. Really here the user could do jobs like fit the back boxes in his shed where he wants them, secure the light fittings, run in the correct mains cabling, drill any holes dig any trenches to make the job as clean and handy for an electrician to do the electrical work. Stay away from the fuse board even with the hole etc. this is afterall a job that many people carryout out themselves and make a mess of it, some people will never get an electrician all we can do is advise them to do so and advise them on what they can do to make is less expensive for them to do the right job.

M cebee

2011 wrote: »

I have never seen this, then again I have not worked in the UK.

My concern would be that the earth fault loop impedance would be too high if this was method was used. A high EFLI would mean that the MCB or fuse would not operate within the specified time.

either 30ma rcd incommer(isolating switch)
or 30ma rcbos on final circuits afaik

if you had a shed 50m from house with extraneous metalwork and you simply wanted a light in the shed - in the uk they would run a 2-core and fit a separate rod

we have the same rules on bonding metalwork in outbuildings don't we?

the 'main bond' is from the house MET?

Bruthal

M cebee wrote: »

either 30ma rcd incommer(isolating switch)
or 30ma rcbos on final circuits

if you had a shed 50m from house with extraneous metalwork and you simply wanted a light in the shed - in the uk they would run a 2-core and fit a separate rod

we have the same rules on bonding metalwork in outbuildings don't we?

the 'main bond' is from the house MET?

300ma you mean? I know years ago thats what i thought I remember it was.

M cebee

Bruthal wrote: »

300ma you mean? I know years ago thats what i thought I remember it was.

for TT to house they used to have 100ma TD incommer on a house and the 30ma sockets downstream afaik

for sheds being wired for TT i think they just use 30ma
incommer or rcbos afaik

it saves the cost of running a main bond from house

in the uk

sumeas

TT?

maxfresh

sumeas wrote: »

TT?

its a earting system ,the consumer must provide there own earth (through an earth rod)

Bruthal

M cebee wrote: »

for TT to house they used to have 100ma TD incommer on a house and the 30ma sockets downstream afaik

for sheds being wired for TT i think they just use 30ma
incommer or rcbos afaik

it saves the cost of running a main bond from house

in the uk

Yea I have 100ma in my other post about main incommer. They might have a time delay to discriminate. Just used to remember in the 80`s something about 300ma main incommer RCD. Cant remember anything anymore.

maxfresh

Bruthal wrote: »

Yea I have 100ma in my other post about main incommer. They might have a time delay to discriminate. Just used to remember in the 80`s something about 300ma main incommer RCD. Cant remember anything anymore.

When i worked on traffic signals the ones on TT supplies (taken from public lighting) had a main 300ma rcd

Bruthal

maxfresh wrote: »

When i worked on traffic signals the ones on TT supplies (taken from public lighting) had a main 300ma rcd

Maybe there is hope for the oul memory yet:)

maxfresh

i think the 300ma is there for fire protection ,much better to have a tncs system with a low earth fault loop impedance in my opinion

M cebee

i don't think 300ma is used for TT

fire yes

i think the 300ma rating for fire is based on 60watt starting a fire

Stoner

ok guys lets keep this thread on target, another thread on RCDs and earthing systems can be started if anyone wishes, no need to confuse the OP anymore.

Bruthal

maxfresh wrote: »

i think the 300ma is there for fire protection ,much better to have a tncs system with a low earth fault loop impedance in my opinion

M cebee wrote: »

i don't think 300ma is used for TT

fire yes

i think the 300ma rating for fire is based on 60watt starting a fire

Its all down to decision makers in an office as to that aspect. 300 will offer fire protection, so will 30, 100 or any of them. But in tt setups, they offer disconnection on earth faults which mcb`s often, if not usually, wont. 30ma ones are primarily for direct contact shock protection. Anything above that are for tripping on earth faults, one (but not the only one) risk of which is fire. Another is protection from indirect shocks from items becoming live during earth faults.


For the OP, the likely best answer is get an electrician to look at it.

paddy147

The poor OP must be lost or totally confused at this point.....:pac::pac:


I know I was with my garage/mews thread....lots of head scratching on my part.:pac::D

maxfresh

Back to the op i would run minimum of 3x 6mm sq to the shed (depends on length of run ,load etc.)

fed from 32 amp mcb in house fuse board

one row fuse board in shed with main switch, 10 amp mcb for lights 20 amp rcbo for sockets

ocj

Just got to read through all the replies,
Thanks,
I have a better idea of what I need now.
The distance from the house to the shed is only 45 meters.

Are there any brick and mortar places around Dublin/Wexford that you guys would recommend for buying the materials?

I have a the metal sockets, switches, fuse board and lights. I just need the cabling now.

paddy147

ocj wrote: »

Just got to read through all the replies,
Thanks,
I have a better idea of what I need now.
The distance from the house to the shed is only 45 meters.

Are there any brick and mortar places around Dublin/Wexford that you guys would recommend for buying the materials?

I have a the metal sockets, switches, fuse board and lights. I just need the cabling now.

Any leccy wholesalers will have all that you need.

Loads in Dublin...(northside and southside)

SWA by the meter,2.5 and 1.5 nymj T&E by the meter,back boxes,sockets,switches,IP Rated board,RCDs and so on.

Stoner

ocj wrote: »

Just got to read through all the replies,
Thanks,
I have a better idea of what I need now.
The distance from the house to the shed is only 45 meters.

Are there any brick and mortar places around Dublin/Wexford that you guys would recommend for buying the materials?

I have a the metal sockets, switches, fuse board and lights. I just need the cabling now.

check here,
http://www.boards.ie/vbulletin/showthread.php?t=2055193263

worth a call beforehand to check if they do sell all the cable by the Meter first rather than getting stung at the counter for 100m

sky6

Hi Lads, I've been reading this thread with interest as I and many Boarders have and want to light Sheds and Garages. I'm now a little confused as I think it failed to answer the basic question of whether you should or can use an Earth Rod to Earth the Garage Sub Board in conjunction with the Earth taken from the main House Board. Not being an Electrician I would have thought that all your doing is ensuring that you have a real good Earth. Or by having both does it make an RCD more difficult to trip. ?

Thanks.

2011

sky6 wrote: »

I'm now a little confused as I think it failed to answer the basic question of whether you should or can use an Earth Rod to Earth the Garage Sub Board in conjunction with the Earth taken from the main House Board.

Normal practice in Ireland would be to take an earth from the house distribution board and not to install an additional earth electrode.

Not being an Electrician I would have thought that all your doing is ensuring that you have a real good Earth.

Think of it this way:
Electricity, like water likes to take the path of least resistance. A typical earth rod resistance to earth would be >100 ohms. Where as the parallel route for the fault current along the earth cable back to the star point of the transformer would be a fraction of this.

Or by having both does it make an RCD more difficult to trip.

No

Bruthal

sky6 wrote: »

Hi Lads, I've been reading this thread with interest as I and many Boarders have and want to light Sheds and Garages. I'm now a little confused as I think it failed to answer the basic question of whether you should or can use an Earth Rod to Earth the Garage Sub Board in conjunction with the Earth taken from the main House Board. Not being an Electrician I would have thought that all your doing is ensuring that you have a real good Earth. Or by having both does it make an RCD more difficult to trip. ?

Thanks.

No extra earth rod used in Ireland.

maxfresh

sky6 wrote: »

Hi Lads, I've been reading this thread with interest as I and many Boarders have and want to light Sheds and Garages. I'm now a little confused as I think it failed to answer the basic question of whether you should or can use an Earth Rod to Earth the Garage Sub Board in conjunction with the Earth taken from the main House Board. Not being an Electrician I would have thought that all your doing is ensuring that you have a real good Earth. Or by having both does it make an RCD more difficult to trip. ?

Thanks.

In the 3 core swa ran to the shed one of the cores is an earth also the steel armor is earthed and is used as the earth as well,

the earthing arangment will not affect the rcd tripping but will affect the mcb operating during a phase to earth fault