Earth connection via SWA

[bigegg]

Just drive an earth spike into the ground next to your shed (and connect to it) and be done with it?

Is that a thing? Genuine question.

Thats plan B.
It means buying a length of 10mm(?) cable, and an Earth rod, and fittings, and a manhole thing - best part of £60
Whereas i already have everything to do the SWA

 

[RWD3M]

Thats plan B.
It means buying a length of 10mm(?) cable, and an Earth rod, and fittings, and a manhole thing - best part of £60
Whereas i already have everything to do the SWA

Always good to have a plan B!

I've got a 10mm 2 core SWA from a 50A MCB in the main house CU that goes to a CU in the Shed. I've connected the steel armour to the earth blocks in both CU's and added another spike at the shed (belt and braces). Nothing's gone amiss yet!

 

[mtt.tr]

Always good to have a plan B!

I've got a 10mm 2 core SWA from a 50A MCB in the main house CU that goes to a CU in the Shed. I've connected the steel armour to the earth blocks in both CU's and added another spike at the shed (belt and braces). Nothing's gone amiss yet!

This can be problematic on pme/tncs supplies.

 

[RWD3M]

This can be problematic on pme/tncs supplies.

How? Again, genuine question.

 

[brightspark]

the op hasn't stated whether he has a pme supply or what the eathing arrangements are it would help rather than making asumptions . my house has pme supply and the shed is fed of an mcb through the house consumer unit and wired in armoured cable it is 3 core but I don't use the 3d core as the earth. in the garage its a tt supply and the braiding armoured is cut off and just bonded at the house db a 3way db is fitted with an 80 amp double pole 30 ma rcd mainswitch. the steelwork is bonded with a bit of 10mm earth wire and an earth rod fitted . it tests out at 8o ohms so is well under 200 max which is allowed . it covers the regulations so that's all that matters. job done

 

[bigegg]

the op hasn't stated whether he has a pme supply or what the eathing arrangements are it would help rather than making asumptions . my house has pme supply and the shed is fed of an mcb through the house consumer unit and wired in armoured cable it is 3 core but I don't use the 3d core as the earth. in the garage its a tt supply and the braiding armoured is cut off and just bonded at the house db a 3way db is fitted with an 80 amp double pole 30 ma rcd mainswitch. the steelwork is bonded with a bit of 10mm earth wire and an earth rod fitted . it tests out at 8o ohms so is well under 200 max which is allowed . it covers the regulations so that's all that matters. job done

Sorry, thought i had.
Its a TNS-C system.
At the house end, swa is (will be) connected to a secondary DB, henley blocked to incomers via an isolator.
DB is connected to an earthing block via a 25mm tail - then via another 25mm tail to the SWA armour.
The 10mm earth core of the Swa will be connected to the earth bar inside the secondary DB.

at other end:
Swa armour to garage DB earth terminal via 25mm tail.

I have a couple of 1m lengths of 25mm tail. (Wickes clearance - 3x1m 25mm tails for a quid. I cleared the shelf, but a lot of them didn't have tbe Earth)

I'd need around 4m of earth cable to connect an earth rod

 

[bigegg]

This can be problematic on pme/tncs supplies.

If the neutral disconnects before your meter, then because the neutral and earth are connected together after that point, every earthed point can then become "live" with a potential depending on the resistance between the point you touch and the earth rod (potentially 200ohms - so if your body has one ohm of resistance to earth, you get 200V+ across you.)

I think.

 

[mtt.tr]

If the neutral disconnects before your meter, then because the neutral and earth are connected together after that point, every earthed point can then become "live" with a potential depending on the resistance between the point you touch and the earth rod (potentially 200ohms - so if your body has one ohm of resistance to earth, you get 200V+ across you.)

I think.

Also your bond could become the only good earth loop which could raise the potential on all metal work that's why the cable is based on incomer size so it can handle the fualt current

 

[brightspark]

outbuilding supplies and earthing explained https://www.voltimum.co.uk/articles/supply-detached-outbuilding-technical

 

[mtt.tr]

outbuilding supplies and earthing explained https://www.voltimum.co.uk/articles/supply-detached-outbuilding-technical

I was struggling to find that link, that's my default reply.

 

[addjunkie]

outbuilding supplies and earthing explained https://www.voltimum.co.uk/articles/supply-detached-outbuilding-technical

No external metalic servces in a steel framed livestock building, does the steel frame need to be earthed?

 

[mtt.tr]

No external metalic servces in a steel framed livestock building, does the steel frame need to be earthed?

Yes, and farms should be on tt by the regs due to step voltages

As in one half of a cow can be at a lower potential than the other tingle tingle pre cooked beef

 

[daedalusminos]

the op hasn't stated whether he has a pme supply or what the eathing arrangements are it would help rather than making asumptions . my house has pme supply and the shed is fed of an mcb through the house consumer unit and wired in armoured cable it is 3 core but I don't use the 3d core as the earth. in the garage its a tt supply and the braiding armoured is cut off and just bonded at the house db a 3way db is fitted with an 80 amp double pole 30 ma rcd mainswitch. the steelwork is bonded with a bit of 10mm earth wire and an earth rod fitted . it tests out at 8o ohms so is well under 200 max which is allowed . it covers the regulations so that's all that matters. job done

This is exactly how I wired mine over a 30m run earth tested out at 125R with single rod with top termination box.

 

[addjunkie]

Yes, and farms should be on tt by the regs due to step voltages

Yes I know, but we're not, neither of my neighbors are.

 

[dobbslc]

@addjunkie
If it's got power to it I would say yes.
Moo Moo's don't like a shock!

 

[brightspark]

No external metalic servces in a steel framed livestock building, does the steel frame need to be earthed?

my supply is tt in metal shed no mains services but the frame is bonded

 

[mtt.tr]

@addjunkie
If it's got power to it I would say yes.
Moo Moo's don't like a shock!

Call the grid to up the transformer tap if its not cooking quick enough ?

 

[mtt.tr]

Yes I know, but we're not, neither of my neighbors are.

Then you need super duper bonding which ultimately costs more than just going to a tt

 

[addjunkie]

@addjunkie
If it's got power to it I would say yes.
Moo Moo's don't like a shock!

No I get that, but, each leg is fixed into the ground with 4 geet big bolts, just like the earth rod, hence why I asked.

 

[brightspark]

No I get that, but, each leg is fixed into the ground with 4 geet big bolts, just like the earth rod, hence why I asked.

in some cases the reinforcing grid can be used instead of an earth rod we all know that the steel p[illars on the building are well in to the ground and serve the same purpose but its well accepted that you have visible earth rod that can be tested . watch any tester and see whats on the report if there isn't one