Power to stables

[Harrymcs]

Hi new to this. Ive been asked to run power to stables 100m from house fb in house has space rcd protected 17th edition board tns system . I have thought about doing two different ways just thought id ask what ppl thot was best. There will be 9 lights and two double sockets in stables

1st way 3core 16mm swa from 40a c/b in house to fb in stable 16a for sockets 6a for lights

2nd way 2core 16mm swa from 40a c/b in house to fb in stable 16a for sockets 6a for lights using earth rod at stable end

Its really the earthing arrangement that im not 100% on due to pd in earth from house to stables

 

[Taylortwocities]

Best to use the earth from the house.
I like to avoid earth electrodes near horse - don't forget the problems this year at Newbury racecourse.

16mm, really? How far is the stables from the house then? It must be miles... Your max demand can never be more than 16+6 = 22amp.

Personally I would feed your circuit on a NON RCD side of the board and have an RCD in the stables. Otherwise the house power will trip in the event of dampness or fault in the stable.

 

[Harrymcs]

Hi thanks for replying so quickly the stables are 100m from house the reason i was goin to use 16mm is the owner is possibly going to build a barn next year

 

[sparkiemike]

16mm, really? How far is the stables from the house then? It must be miles... Your max demand can never be more than 16+6 = 22amp.

With volt drop for a lighting circuit and a max load of about 5kW, 16mm2 would be about right for a 100m run

 

[Taylortwocities]

Ahh. I missed the 100metre bit

 

[ericmark]

705.411.4 TN system
A TN-C system shall not be used in the installation. This requirement applies also to residences and other locations belonging to agricultural or horticultural premises according to the definition of "Residences and other... premises" (see Part 2 ).

705.415.2.1 Additional protection: Supplementary equipotential bonding
In locations intended for livestock, supplementary bonding shall connect all exposed-conductive-parts and extraneous conductive-parts that can be touched by livestock. Where a metal grid is laid in the floor, it shall be included within the supplementary bonding of the location (Figure 705 shows an example of this. Other suitable arrangements of a metal grid are not precluded).
Extraneous-conductive-parts in. or on, the floor. e.g. concrete reinforcement in general or reinforcement of cellars for liquid manure, shall be connected to the supplementary equipotential bonding.
It is recommended that spaced floors made of prefabricated concrete elements be part of the supplementary equipotential bonding. The supplementary equipotential bonding and the metal grid, if any, shall be erected so that it is durably protected against mechanical stresses and corrosion.
NOTE: Where a metal grid is not laid in the floor a TN-C-S supply is not recommended.

Fig 705 on page 187 shows the earthing arrangement with that amount of metal in the ground there should be a really good earth. The real problem is size of earth cable. Should there be a fault the current could be very high and even if the supply is only 5 amp likely it will still need a 16mm sq earth cable if the TN-C-S earth is connected. I would consider TT would be better idea.

 

[ricicle]

Hi new to this...

How new ?

 

[bernardgreen]

Best to use the earth from the house.
I like to avoid earth electrodes near horse - don't forget the problems this year at Newbury racecourse.

Wasn't the incident at Newbury caused by a leak to ground from a Live conductor in cable damaged during work in the arena.

The risk of importing the "earth" from the house is that the house "earth" may be a few volts above ground potential and a horse entering or leaving the stable may bridge between true ground and something at house "earth" potential. If only needs couple of volts to spook a horse.

So my opinion is TT for the stable. I would also consider the need to have the stable CU well away from the "kick zone" of a horse and also reachable when there is a spooked horse in the stable. So a weather proof box outside the stable might be worth considering.

And when you lay in the cable for the power run in some cables for telehone, maybe a panic button, alarm cable ( horse thieves in mind ) etc etc