Wiring greenhouse

[thedawnbefore]

Hi, I'd be grateful for some pro. advice on the best cable choice and termination throughout a domestic greenhouse.

The building is relatively large at about 100sqft and will naturally be a permanently hot, wet, 100% humidity and UV-intense environment. The building will have an IP56-rated consumer unit professionally installed inside.

From there I was thinking:

• 5ft IP56 non-corrosive LED batten & switch
• x2 1 gang IP65 sockets at each end (one powering a 2kw heater for long periods of time)
• x1 2 gang socket on the exterior

PVC Conduit will be difficult because of the building corners and I'd prefer not to use the flexible stuff. Should I use 2.5/4mm SWA throughout or is this overkill - is there a better cable type available that is suitable for permanent fixing and this environment?

Any advice sincerely appreciated. Many thanks.

 

[Pete999]

Hi, I'd be grateful for some pro. advice on the best cable choice and termination throughout a domestic greenhouse.

The building is relatively large at about 100sqft and will naturally be a permanently hot, wet, 100% humidity and UV-intense environment. The building will have an IP56-rated consumer unit professionally installed inside.

From there I was thinking:

• 5ft IP56 non-corrosive LED batten & switch
• x2 1 gang IP65 sockets at each end (one powering a 2kw heater for long periods of time)
• x1 2 gang socket on the exterior

PVC Conduit will be difficult because of the building corners and I'd prefer not to use the flexible stuff. Should I use 2.5/4mm SWA throughout or is this overkill - is there a better cable type available that is suitable for permanent fixing and this environment?

Any advice sincerely appreciated. Many thanks.

What do you mean 2.5/4mm? and a professionally installed CU?

 

[James]

I think you would be well advised to ask these questions to the professional that is installing the distribution board.
The whole thing is likely to come under part p and require notifications.
If ratings and uv protection are important here,
Permanent heaters would be better with a dedicated supply and will need to be suitable for the environment, an off the shelf fanheater is not likely to be ok.

Mechanical protection of cables might be an issue, a pair of pruning shears will make a mess of the wrong type of cable.

 

[thedawnbefore]

What do you mean 2.5/4mm? and a professionally installed CU?

Thanks.

Small Consumer Unit going into the Greenhouse to support internal lighting, the various 13A sockets. I should have mentioned there will be an underground pump to rainwater tank on another circuit next year.

https://www.screwfix.com/p/british-...FRzLDmFs-tdSTvgEpNYaAnGdEALw_wcB&gclsrc=aw.ds

I was considering fixing 2.5mm or 4mm armoured SWA throughout but wondering if NYY-J might suffice given the low mechanical risk? Thank you.

 

[Dustydazzler]

Last commercial greenhouse I wired we did the entire install in 2.5mm swa and metal clad switches & sockets , swi fuse for the lights...
led Ip rated Strip lightsl
looked really nice install and one of my favourite jobs I done recently

 

[Spoon]

Welcome to the forum mate.
As mentioned above, this is a new circuit and falls under Part P and the work is notifiable.
Are you getting an electrician in to do this work?

 

[thedawnbefore]

Last commercial greenhouse I wired we did the entire install in 2.5mm swa and metal clad switches & sockets , swi fuse for the lights...
led Ip rated Strip lightsl
looked really nice install and one of my favourite jobs I done recently

Thanks! That's helpful.

 

[telectrix]

need moree than 2.5mm for a 100sq.ft. of cannabis plants. ( whereas all the smileys gone. long time missing).

 

[thedawnbefore]

Welcome to the forum mate.
As mentioned above, this is a new circuit and falls under Part P and the work is notifiable.
Are you getting an electrician in to do this work?

Thank you, that's v. helpful as i hadn't considered the Part P regs so will ask a professional to do the entire fix as you and James have recommended.

Out of interest is NYY-J cable likely to be suitable for fixed installation to these 13A outlets and lighting? And if so would you go with 2.5mm or 4mm? I'll probably build all the various mountings myself and the number and placement of these might depend on the flexibility of cable and installation time..

 

[telectrix]

NYY-Y should be ideal. gland into accessories with flex glands. smaller sizes (up to 10mm) generaly are solid core (like T/E) so no need for end ferrules. make all bends gentle rather than sharp.

 

[Spoon]

Thank you, that's v. helpful as i hadn't considered the Part P regs so will ask a professional to do the entire fix as you and James have recommended.

Out of interest is NYY-J cable likely to be suitable for fixed installation to these 13A outlets and lighting? And if so would you go with 2.5mm or 4mm? I'll probably build all the various mountings myself and the number and placement of these might depend on the flexibility of cable and installation time..

Regarding the cable size. I'd leave that to the electrician doing the work. Out of curiosity, what would be the ambient temperature inside the greenhouse as this will affect the cable size?

I should have mentioned there will be an underground pump to rainwater tank on another circuit next year.

Is this going to be wired back to the greenhouse?
What size is the pump?
This needs to be taken into account when fitting the CU into the greenhouse and the overall load of the circuit.

 

[thedawnbefore]

2.5mm or 4mm? I'll probably build

Regarding the cable size. I'd leave that to the electrician doing the work. Out of curiosity, what would be the ambient temperature inside the greenhouse as this will affect the cable size?



Is this going to be wired back to the greenhouse?
What size is the pump?
This needs to be taken into account when fitting the CU into the greenhouse and the overall load of the circuit.

Thank you. The pump is a specialist thing designed for underground rainwater tanks ~1100W @ 240V. Standard 13A although I would expect this to be hardwired into the greenhouse and on a dedicated circuit. The temperature inside the greenhouse will range from -15 in winter to around 45C in summer. Often 100% humidity. Frequently exposed to water/sprinklers inc. mildly acidic chemicals.

https://www.rainwaterharvesting.co.uk/rainwater-pumps/1100w-evolution-x-aje-80-steel-pump-37