How to run cable over a bridge / Regulations on PV cabling

[MXDDXM]

I'm considering ground mounting a 10kW system in the field next to my house. To hook it up to the house, I need to run it underground in the field for ~10 meters, then (I imagine) along the underside of bridge going over a small stream for ~5meters, and finally another 25 meters to the house.

The question is, what rules apply in the U.K. for cable runs between arrays and the hook-up to the house?
Can I surface the cable by the bridge, tack it the wooden bridge underside and then bury it again?

Thanks

 

[12VoltInstalls]

U.K.

No clue

Can I surface the cable by the bridge, tack it the wooden bridge underside and then bury it again?

I don’t know UK but how deep is the stream? 16-feet or so I’d be asking myself if I should just bury the conduit deep under the streambed and not daylight it at the bridge.

I’d likely hire an electrician an hour for consultation and have ‘em write down the local “code” requirements and do that. Sometimes the small investment to consult a qualified license is cheaper and less troublesome even if you don’t have to do it twice.

 

[Osmethne]

No idea about code here but I would avoid the riverbed. I think mounting to the underside of the bridge is a better plan. Definitely run it through conduit on the bridge. This is assuming the bridge is in decent condition.

 

[12VoltInstalls]

would avoid the riverbed.

There’s cabling and communication under rivers and estuaries all over. Underground in conduit is the safest place.

 

[SeaGal]

I'm considering ground mounting a 10kW system in the field next to my house. To hook it up to the house, I need to run it underground in the field for ~10 meters, then (I imagine) along the underside of bridge going over a small stream for ~5meters, and finally another 25 meters to the house.

The question is, what rules apply in the U.K. for cable runs between arrays and the hook-up to the house?
Can I surface the cable by the bridge, tack it the wooden bridge underside and then bury it again?

Thanks

I'm not a sparky, but understand that BS7671 will apply.

You have only specified "system" and "cable" without it being clear whether you want to run PV cable (dc) from panels to an inverter in the house, or whether the "system" comprises both panels an inverter and you want to get 230V AC back to the house.

Assuming the former (which is more logical from carry power over a distance) then PV cable itself is not suitable for direct burial - it will need to be in double walled ducting as minimum, correctly coloured and to the required safe depth. There will need to be warning tape below ground, but above the ducting too.

Unless the location is a specific case covered by BS7671 (such as a campsite) then the key consideration is whether the cable will be safe from external interference, so my concerns with coming up and across the bridge would be protection not only from water ingress, but from physical damage - e.g. someone brush-cutting weeds at ground level by the bridge. Hence, metal conduit would be advisable, but then you would also need to be able to achieve a water-tight joint underground between the metal conduit and remaining, presumably double skinned plastic, ducting for the remaining run.

If the bridge is not sturdy, IMHO it would be better to go underground or have a completely separate metal conduit structure to carry the cables, suitably labelled, of course.

If, on the other hand, you want to transmit mains power back, then SWA of maximum size would suffice for direct burial and not require extra complexity around the bridge.

 

[k490]

How would you go under a streambed unless you pay for a horizontal drilling machine like this one.

 

[12VoltInstalls]

How would you go under a streambed unless you pay for a horizontal drilling machine like this one.

An excavator - depending on local regulations. A stream of 10-20’ wide can get trenched, conduit laid, then reburied.

 

[SeaGal]

Agree... if the bridge is only 5m wide, I doubt the 'stream' would be much more than a few feet wide, especially in the summer.