D.C. Cables

[edexlab]

use good european pv low power loss dc cables 4/6mm2
most are not very good quality look for tuv specs and designed for 25/30years lifespan
keep dc runs short as possible 10metre is good practice
you could try mounting the inverter & dc isolator outside most goods ones are waterproof IP65

Why limit Dc cable run to 10 metres?

 

[daytona600]

to lower power loss and keep yield of system as high as possible
600/1000vdc quite dangerous in domestic roofs/attics/garage
eg in event of a fire during daylight unless pv fireman switch is used or rodents/children damaging conductors
good pv cable eg 4mm2 low power loss - 55amps 1800vdc - halogen free - cross linked - uv resistant for 30years & very high short circuit proof
on pv parks/trackers inverters are mounted directly onto the back of the racks and dc converted to ac as quick as possible

 

[edexlab]

to lower power loss and keep yield of system as high as possible
600/1000vdc quite dangerous in domestic roofs/attics/garage
eg in event of a fire during daylight unless pv fireman switch is used or rodents/children damaging conductors
good pv cable eg 4mm2 low power loss - 55amps 1800vdc - halogen free - cross linked - uv resistant for 30years & very high short circuit proof
on pv parks/trackers inverters are mounted directly onto the back of the racks and dc converted to ac as quick as possible

Valid points above

any voltage present in Ac or Dc circuits is dangerous and a fire risk and I do think that the firemans switch is a good idea

However if installed correctly I see no reason why you can't have longer runs
Also on large pv systems ie >100kw it is common practice to run the dc from the arrays as far as 70 metres to central inverters, I realise this is not the same as a domestic install.
If the installer has thought about this and is implementing sensible practices and installation methods following the regs then how can it be viewed as a bad practice
I would argue that putting the inverter in the attic is though.

 

[daytona600]

pv fireman switch used in germany/continent generally on commercial systems to remotely isolated the system
no problems using longer runs as long as its good pv low loss cables
problem most suppliers/wholesalers supply the cheap stuff

nb you have to take in to account 95% of mcs installers where installing windows or kitchens last year
power loss , cable runs . best practice mean nothing to them
had one that installed a 4kwp ground system with 200metres dc cable runs !! and one that fitted a indoor inverter outdoor on a roof
most have have no electrical background , usually buying from the lowest bidder

n

Valid points above

any voltage present in Ac or Dc circuits is dangerous and a fire risk and I do think that the firemans switch is a good idea

However if installed correctly I see no reason why you can't have longer runs
Also on large pv systems ie >100kw it is common practice to run the dc from the arrays as far as 70 metres to central inverters, I realise this is not the same as a domestic install.
If the installer has thought about this and is implementing sensible practices and installation methods following the regs then how can it be viewed as a bad practice
I would argue that putting the inverter in the attic is though.