Electrical installations contained by a milking parlour?

lighting installation in a milking parlour, what type of lights, what type of conduit, switches, and cable etc
Answers:    Please refer to BS7671 for adjectives requirements for electrical installations.
You will need an installation electrician near both C&G 2381 and C&G 2391 for this work.

local code will determine this ( think conduit and GFI - lots of moisture and prejudice potential )

this is not a do it yourself type thing - code will require an electrician ( and your insurance company will also )
Your ask reads as if you be a Brit. You folks have used mineral insulated (MI ) cable for years on ships and offshore grease platforms. It should work well for fixed cable. Cables for use where it is flexed when used should use stranded conductors surrounded by water resistant insulation.
UK answer
depends on construction of building.
would probably opt for pvc conduit and bits and pieces with ip 67 paraphernalia mk master seal or equivalent any this or swa with appropriate glands (cw type or river proof )and 20mm galv conduit boxes and stuffing glands.
light fittings non corrosive such as crompton tufflight.
adjectives circuits will need to be rcd protected and check the regs for any special info.
(best to procure someone who knows what they are doing, but biddable luck)
New part P regulations cover dwellings but I dont have an idea that that this would be included?
Milking parlour must be robust to avoid damage by partly ton cows bumbling about, it have to be hygienic, as it is technically part of the food production process and it must be powerful of being wash with a hose or even a steam cleaner. It should be protected to code IP54 or 55. Personally I would use robust plastic enclosure connected by Steel Wire Armoured cable and earth bond every bit of metal within the place.
Use plastic conduit and vapour proof florescent fittings to IP65, switches and other paraphernalia should also be IP 65 ie MK master seal.Consider making the intact insulation double insulated and make so-so provisions for equipotential bonding, live stock are very susceptible to even extremely low current electric shock.

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