Solar panel circuit MCB size?

[driverman]

i would of tried getting the inverter closer to the array or used micro inverters.

I know nothing about solar installations, just doing to their spec. The distance between the two is not that great really. I would say the depth of a bedroom 3.4m ish plus another 3m. Would you consider that a long DC run? For whatever reason customer or installers wanted the inverter on the ground floor. Possibly for maintenance? Save going up into the loft? I don't know really,I'm just trying to get it done! lol

 

[Gavin A]

i think burying DC cables in the wall is an awful idea IMO

If it's mechanically protected what's the issue?

 

[shanky887614]

nothing wrong with it but i prefer the inverter up in the loft.

that way only the ac cable goes to meter then board

 

[TJ Anderson]

Of course you won't have, a 16A mcb will handle 16A, that's the whole point of it being a 16A rated device.

All well and good as long as G/83 settings applied which limit output. These inverters are made to work in different markets. We had an SMA TL 4.0 that went quite a bit over before it was realised.

 

[Leesparkykent]

Because in my view burying them in the wall even in galv conduit, customer turns main switch off in house for whatever reason they still have live cables running down the wall buried! the customer doesn't know they are there, only the person who done the install will.

 

[Gavin A]

nothing wrong with it but i prefer the inverter up in the loft. Reply With Quote

that way only the ac cable goes to meter then board

reasons not to would include the inverter operating at a higher ambient air temperature when at peak output, and therefore reducing the lifespan of the inverter (which ultimately is dictated by the lifespan of the capacitors), dustier environment, and the inverter being less accessible to check for repairs.

We'll install in lofts when there's no other option, but our preference is for the inverter in a garage or other accessible cooler space within the house if there is the option for those reasons.

 

[davesparks]

Because in my view burying them in the wall even in galv conduit, customer turns main switch off in house for whatever reason they still have live cables running down the wall buried! the customer doesn't know they are there, only the person who done the install will.

Then perhaps the customer should read the label at the CU which warns of the dual supply and the location of isolators required to achieve complete isolation

 

[Leesparkykent]

reasons not to would include the inverter operating at a higher ambient air temperature when at peak output, and therefore reducing the lifespan of the inverter (which ultimately is dictated by the lifespan of the capacitors), dustier environment, and the inverter being less accessible to check for repairs.

We'll install in lofts when there's no other option, but our preference is for the inverter in a garage or other accessible cooler space within the house if there is the option for those reasons.

agreed but could possibly go in a cuopboard upstairs etc, or just use enphase.

 

[Leesparkykent]

Then perhaps the customer should read the label at the CU which warns of the dual supply and the location of isolators required to achieve complete isolation

hows that going to stop the dc cables from being live? is there an isolator to turn the sun off? lol

 

[davesparks]

All well and good as long as G/83 settings applied which limit output. These inverters are made to work in different markets. We had an SMA TL 4.0 that went quite a bit over before it was realised.

I don't understand, how will the settings cause a 16A mcb to not be able to handle 16A? That is what my post stated, a 16A mcb will be fine with 16A flowing through it.

If what you are saying is that if the inverter could deliver more than 16A if not correctly set up then obviously that is a different scenario.

 

[davesparks]

hows that going to stop the dc cables from being live? is there an isolator to turn the sun off? lol

I don't know, I don't install solar. But I do have some common sense and that says you would have a DC isolator where the cables enter the property to isolate them.

 

[TJ Anderson]

hows that going to stop the dc cables from being live? is there an isolator to turn the sun off? lol

I was thinking the same, unless he has DC isolators upstream of the buried section. Unlikely though, probably just next to inverter.

 

[Gavin A]

Because in my view burying them in the wall even in galv conduit, customer turns main switch off in house for whatever reason they still have live cables running down the wall buried! the customer doesn't know they are there, only the person who done the install will.

again, if it's mechanically protected what's the problem?

and I mean mechanically protected with proper 3mm thick galv steel.

The stickers on the consumer unit, and fact there's an inverter downstairs and panels on the roof ought to give an indication that there are live dc cables in the wall. We'll always put a DC isolator in the loft as well so it can be isolated if needed.

 

[Gavin A]

hows that going to stop the dc cables from being live? is there an isolator to turn the sun off? lol

isolator in the loft.

 

[Leesparkykent]

I don't know, I don't install solar. But I do have some common sense and that says you would have a DC isolator where the cables enter the property to isolate them.

yea 9X out of 10 the dc cables will enter the loft so prob would be best to stick a dc isolator there also but the customer aint climbing in to the loft to isolate this are they! they will just crank the ac and dc isolator off at the inverter ( in this case its going to be next to the consumer unit) hence leaving the buried DC cables live in the wall when the main switch at consumer unit,ac isolator/dc isolator at the inverter are all off.

 

[TJ Anderson]

isolator in the loft.

Even if there was, which is unlikely if the inverter in elsewhere (very commendable of you though), the customer would just switch of Main AC Isolator for PV (by CU) and assume they had done it. Then they would still get a free crash course in arc welding when they get their drill out.

 

[davesparks]

yea 9X out of 10 the dc cables will enter the loft so prob would be best to stick a dc isolator there also but the customer aint climbing in to the loft to isolate this are they! they will just crank the ac and dc isolator off at the inverter ( in this case its going to be next to the consumer unit) hence leaving the buried DC cables live in the wall when the main switch at consumer unit,ac isolator/dc isolator at the inverter are all off.

Then if they can't read a label which clearly states how to isolate correctly what hope has the human race really got?
So what exactly is this scenario you are describing here, why is the customer trying to isolate the installation in the first place?

 

[Leesparkykent]

again, if it's mechanically protected what's the problem?

and I mean mechanically protected with proper 3mm thick galv steel.

The stickers on the consumer unit, and fact there's an inverter downstairs and panels on the roof ought to give an indication that there are live dc cables in the wall. We'll always put a DC isolator in the loft as well so it can be isolated if needed.

of course because it will always be an electrician who buys this new build house and knows the ins and outs of an electrical installation/PV system so will automatically assume all this. behave! lol

 

[Gavin A]

I don't understand what it is you think a house owner is going to be doing to result in them attacking the wall with such force that they can end up breaching the protection of heavy duty galv conduit before realising that they've hit something hard and metallic and should probably stop attacking it and work out what it is.

 

[Leesparkykent]

because diy dave has got his big shiny drill out on a sunday!