Conduit used for mechanical protection only

[driverman]

What are your thoughts using metal conduit just for mechanical protection. In the past the regs said if a short piece of metal protection was used for just mechanical protection it needn't be earthed. The reason I ask is that I've just installed 2 x 20mm lengths flush side by side for the solar electrical cables from loft to inverter / mains position.
Each length 3.75m long. That possibly not a short length. I have installed an earth wire to loft space and will earth them using clamps. Just wondered though, is it really necessary to comply with 17th? Thanks

 

[Rockingit]

Depends on what cable is inside them. I would have said if sheathed then no, if singles then yes. However, if you draw an example from armoured cable, it's required to earth the armour irrespective of whether it's used as a cpc or not.

 

[shanky887614]

What are your thoughts using metal conduit just for mechanical protection. In the past the regs said if a short piece of metal protection was used for just mechanical protection it needn't be earthed. The reason I ask is that I've just installed 2 x 20mm lengths flush side by side for the solar electrical cables from loft to inverter / mains position.
Each length 3.75m long. That possibly not a short length. I have installed an earth wire to loft space and will earth them using clamps. Just wondered though, is it really necessary to comply with 17th? Thanks

have a look at earth couplers mate, even if you have to use a nipple in future.

its looks better imho.

 

[Andy78]

Any exposed conductive parts must be earthed. If it's not exposed it may not need earthing.

If it is to provide protection so you can avoid using RCD protection for cables buried less than 50mm then it must be earthed.

 

[driverman]

Depends on what cable is inside them. I would have said if sheathed then no, if singles then yes. However, if you draw an example from armoured cable, it's required to earth the armour irrespective of whether it's used as a cpc or not.

I know nothing about Solar wiring etc. The cable that will be in the conduit are those that come from the roof panels via their 2 x rotary isolation switches which are sited in the loft. The PVC sheath cable sizes are small in dia.

 

[Silly Sausage]

Why are you using metal tube?
Heavy duty PVC pipe would save you this earthing problem.

 

[shanky887614]

I know nothing about Solar wiring etc. The cable that will be in the conduit are those that come from the roof panels via their 2 x rotary isolation switches which are sited in the loft. The PVC sheath cable sizes are small in dia.

? so the inverter is downstairs?

most installs ive come across have the inverter in the loft, that way only one cable needs to go downstairs

 

[driverman]

have a look at earth couplers mate, even if you have to use a nipple in future.

its looks better imho.

Was going to use brass female bushes on conduit in loft. I did ask ay wholesalers for rubber female bushes (no jokes plz) that just slip on the end of the conduit, but they knew nothing about them. At other end the same or male bushes as coupler there already.

 

[driverman]

? so the inverter is downstairs?

most installs ive come across have the inverter in the loft, that way only one cable needs to go downstairs

Yes inverter going downstairs in cupboard where the consumer will be sited also.

 

[telectrix]

fit couplers and bushes to conduit. at 1 end fit banjos. then use the 6mm hole in the banjos for your earth terminal.

 

[driverman]

Why are you using metal tube?
Heavy duty PVC pipe would save you this earthing problem.

Solar people requested it. Conduit flush in corner of ground floor room rising in corner of bedroom above to loft.
Personally i would of fitted metal anyhow for better mechanical protection.

 

[driverman]

fit couplers and bushes to conduit. at 1 end fit banjos. then use the 6mm hole in the banjos for your earth terminal.

Conduit not being terminated anywhere. solar people just want conduit end in loft........and other open end in cupboard below. I did suggest Besa box.

 

[Silly Sausage]

Solar people requested it. Conduit flush in corner of ground floor room rising in corner of bedroom above to loft.
Personally i would of fitted metal anyhow for better mechanical protection.

Ah, hence your post in t'other thread!

 

[driverman]

Ah, hence your post in t'other thread!

ohhh yes. I forgot all about that. must learn how to look back on threads. At first i thought it was your sharp wit re thread / conduit. lol

 

[ayjay]

i don,t think steel conduit running down the bedroom wall will be acceptable to the home owner

 

[driverman]

i don,t think steel conduit running down the bedroom wall will be acceptable to the home owner

Conduit will be flush in the corner within 150mm (safety zone) Is that not acceptable?

 

[davesparks]

i don,t think steel conduit running down the bedroom wall will be acceptable to the home owner

Why not? They won't see it as it is going to be flush.

 

[Deleted member 72666]

Can't see what the problem is, just twist the conduits together and pop them into some sleeving...... or have I posted on the wrong thread?

 

[Adam W]

Are the cables going in them ac or dc? And what voltage are they? I don't know much about solar - most of the threads in the solar category confuse the bejesus out of me.

 

[ayjay]

probably24vdc adam
-----------------

regarding chasing in ,is the house occupied and decorated?

 

[Adam W]

If it's 24vdc I probably wouldn't bother earthing it.

 

[Risteard]

probably24vdc adam

It'd be a hell of a lot higher than that.

 

[shanky887614]

If it's 24vdc I probably wouldn't bother earthing it.

are you serious?

usually its between 200-700v going through those solar panel cables

i spotted a 3ph solar install that had 650 something volts on one string

 

[davesparks]

regarding chasing in ,is the house occupied and decorated?

Does it matter, the OP is only asking if a flush steel conduit needs earthing!

 

[Adam W]

are you serious?

usually its between 200-700v going through those solar panel cables

i spotted a 3ph solar install that had 650 something volts on one string

Read post #19.

 

[shanky887614]

Read post #19.

it will be dc.

the solar panels themselfs are dc. they then go to the inverter then the outout is at 230/415v ac

 

[D Skelton]

I do it all the time. T+E down buried galv drops when a circuit has no current RCD protection, or I've designed it to be without RCD protection.

 

[driverman]

I do it all the time. T+E down buried galv drops when a circuit has no current RCD protection, or I've designed it to be without RCD protection.

Inverter will be sited downstairs near mains position. Solar people have requested that a spare way within the consumer unit be made available to them. Therefore the cables in the conduit will be DC from solar panels. Just to reaffirm, i know nothing at all about solar panels etc. A learning curve with interest.

 

[D Skelton]

Inverter will be sited downstairs near mains position. Solar people have requested that a spare way within the consumer unit be made available to them. Therefore the cables in the conduit will be DC from solar panels. Just to reaffirm, i know nothing at all about solar panels etc. A learning curve with interest.

Poor design by the solar lot I'd say. Ideally, you want to keep your DC runs to a minimum, hence why inverters are often sited in lofts or upstairs cupboards. That said, as long as the DC cables are protected from penetration if buried in a wall then I can't see a major problem with it. The conduit won't be classed as an exposed conductive part so won't need earthing. That said, even if it was earthed, it would have no effect whatsoever.

 

[driverman]

Poor design by the solar lot I'd say. Ideally, you want to keep your DC runs to a minimum, hence why inverters are often sited in lofts or upstairs cupboards. That said, as long as the DC cables are protected from penetration if buried in a wall then I can't see a major problem with it. The conduit won't be classed as an exposed conductive part so won't need earthing. That said, even if it was earthed, it would have no effect whatsoever.

Thanks for that. I will ask Solar people/ customer as to why inverter down stairs out of interest. There is plenty of room in the loft. They have installed 2 x rotary isolators in the loft in readiness to take cables down to mains via conduits.