DC cable run?

[mark da spark]

Hi,

We've just been to look at a job where the customer would like the inverter next to consumer unit as there is no loft to site it. The dc cable run would be around 10m.

Is this length of run ok as it stats in dti guide to keep dc run as short as possible.
If yes, can it be run in plastic conduit down the gable of property and label it with warning stickers?

Cheers, Mark

 

[SolarCity]

The DC cable run of 10m would be fine for volt drop - also, siting outside of the loft is a pretty good option as the heat and dust in lofts can be a problem.

As for warning stickers, not sure they are required.

Not sure what the regulation is for these DC runs. Is it acceptable to have the cables chased into the walls? Could be dangerous, particularly with TL inverters. (I know this isn't applicable to your question, but it is relevant to the broader subject)

 

[mark da spark]

I did think the voltage drop would be minimium on that length of run.
As for the lofts they are very dusty and do to get hot on our 7 days of summer. Some people do prefer them up there out of the way.

On the TL inverters side of things?
When earthing the array, is it a matter of earthing (10mm earth) one point because the whole roof mounting frame and panels are connected together?

 

[SolarCity]

I'd say that was a judgement call. I'd probably go on the safe side and bond all of the rails.

 

[edexlab]

Hi,

We've just been to look at a job where the customer would like the inverter next to consumer unit as there is no loft to site it. The dc cable run would be around 10m.

Is this length of run ok as it stats in dti guide to keep dc run as short as possible.
If yes, can it be run in plastic conduit down the gable of property and label it with warning stickers?

Cheers, Mark

Done exactly this quite a few times also had last Mcs inspection on a job like this with external Dc in conduit , I label the tube in a couple of places and Mcs man commented that this is one of the things they want to see

as for Dc cable runs you can comfortably go further than 10 m on systems around 3-4kw do the calcs and you'll see.
also on dc runs which are in areas which could be damaged it's not a bad idea to run +/- in separate conduits spaced apart
ie you've got to damage both to be at risk of shock or arcing

 

[SolarCity]

also on dc runs which are in areas which could be damaged it's not a bad idea to run +/- in separate conduits spaced apart
ie you've got to damage both to be at risk of shock or arcing

Even on inverters without galvanic isolation? Is it not possible for a potential to exist between one of the DC cables and the house earth?

Also, I'm not sure seperating DC cables is a good idea. Does this not increase the potential damage caused by lightning?