Solar PV wages

[tom262]

Hello, I was Approched by a company about 6 months ago to install all there solar and help price as a sub contractor, I used to fit solar a few years ago in a previous company but never had anything to do with pricing or anything like that, I put myself though the courses put my apprentice though working at heights courses ect brought new access equipment ect, but don't know what to charge, or what the going rate is?? Cheers

 

[Mark Cranmer]

I charge 450 a job for a 2 man team
We supply all AC Cable 2.5mm and tails
clips and screws then we also provide the roof fixings
'Sundries'

That includes the 100mile geographical spread and the Part P notification

I know some companies give more money. as for access equipment ladders? Because unless its a bungalow or has an adjoining wall to the roof I would only work on scaffolded jobs

It gets tricky as it is for doing contracting in the fact that unless you have done over 30k in the last business year in just labour cost then it still comes under CIS therefore the Installlation/Sales Company will/should charge the CIS for you then you would need to do the same for your roofer or team!
So for me I lose money every job until april!

 

[infinity]

£450 just for electrical side or roofing As well.
And you shouldn't be using anything smaller than 4mm T&E !

 

[Leesparkykent]

I charge 450 a job for a 2 man team
We supply all AC Cable 2.5mm and tails
clips and screws then we also provide the roof fixings
'Sundries'

That includes the 100mile geographical spread and the Part P notification

I know some companies give more money. as for access equipment ladders? Because unless its a bungalow or has an adjoining wall to the roof I would only work on scaffolded jobs

It gets tricky as it is for doing contracting in the fact that unless you have done over 30k in the last business year in just labour cost then it still comes under CIS therefore the Installlation/Sales Company will/should charge the CIS for you then you would need to do the same for your roofer or team!
So for me I lose money every job until april!

This is 2 cheap imo, think of the fuel alone on a 200 mile round trip , price of cable, bonding, trunking, conduit,clips,administration, insurances, general wear and tear on vehicle the list goes on ...

 

[Englishman]

£450 just for electrical side or roofing As well.
And you shouldn't be using anything smaller than 4mm T&E !

Don't do any pv myself but come across a fair bit and have never known if done in anything but 2.5.

 

[shanky887614]

£450 just for electrical side or roofing As well.
And you shouldn't be using anything smaller than 4mm T&E !

why for the ac side a 4kw system can only output a max of 17amps.

 

[Gavin A]

Don't do any pv myself but come across a fair bit and have never known if done in anything but 2.5.

because it's been installed by muppets working for companies who've not got a clue.

ALmost all the rent a roof rubbish has been done like this, then they wonder why they get loads of over voltage issues and the DNO laughs at them when they try to get the DNO to change the tappings.

Personally I don't mind too much as it means on any streets we install on with other systems in place, then the chances are it will be their inverters start tripping out first due to overvoltage, not ours.

 

[shanky887614]

Don't do any pv myself but come across a fair bit and have never known if done in anything but 2.5.

the dc side is 4mm but the ac side is usually 2.5

 

[Gavin A]

why for the ac side a 4kw system can only output a max of 17amps.

volt drop should be under 1% at full power, otherwise it risks the inverter tripping out due to the over voltage limits.

or more basic than that, because the manufacturers say so.... but that's the reason.

 

[Englishman]

the dc side is 4mm but the ac side is usually 2.5

The ac is what I'm talking about, sorry, should have mentioned.



*i await my stalker*

 

[shanky887614]

that is %1 to the charger if its charging a battery not to the grid

this is the mcs guide and the only reference to 1%

 

[Leesparkykent]

1% is recommended, 3% is what the regs allow. Think about it though for return on investment you want as little as volt drop as possible.
for example; a 4KW inverter, 3% loss is 120 watts, 1% loss is 40 watts. Therefore limiting the voltage rise to the recomended 1% rather than the maximum permitted 3% saves 80 watts.

 

[Gavin A]

that is %1 to the charger if its charging a battery not to the grid

this is the mcs guide and the only reference to 1%

you really want to do this?

The a.c. cable connecting the inverter(s) to the consumer unit should be sized to minimise voltagedrop. A 1% drop or less is recommended. However in larger installations this may not be practicable
or economic due to the very large size of cable resulting. In this case the designer should minimise
voltage drop as far as possible and must remain within voltage drop limits as prescribed by BS 7671.
Note: The recommendation for a 1% voltage drop is due to two reasons: firstly when generating,
the voltage at the inverter terminals is higher than the voltage at the supplier’s cutout – during
periods of high power output this voltage drop must be kept to a minimum in order to prevent the
inverter nuisance tripping on over voltage ; secondly the requirement ensures losses from the PV
system are minimised.

mcs guide


as I said..... kinda ****es me off the huge number of sparks seem to not be able to grasp this fairly basic concept for solar PV installations really. It's right there in plain english in the guidance they're all supposed to follow as well as in the inverter manufacturers instructions. It's really not that difficult a concept to grasp, and yet probably at least half of all solar PV systems have been installed with this wrong and will be more prone to over voltage trip out issues as a result.

Probably stems from apparently being qualified after attending a basic 3 day course mostly led by instructors who've only got the most basic grasp of the subject themselves I suppose, but it's still right there in all the guidance and instruction manuals.

eta - plus the financial losses to the customer.

 

[Leesparkykent]

you really want to do this?


mcs guide


as I said..... kinda ****es me off the huge number of sparks seem to not be able to grasp this fairly basic concept for solar PV installations really. It's right there in plain english in the guidance they're all supposed to follow as well as in the inverter manufacturers instructions. It's really not that difficult a concept to grasp, and yet probably at least half of all solar PV systems have been installed with this wrong and will be more prone to over voltage trip out issues as a result.

Probably stems from apparently being qualified after attending a basic 3 day course mostly led by instructors who've only got the most basic grasp of the subject themselves I suppose, but it's still right there in all the guidance and instruction manuals.

eta - plus the financial losses to the customer.

Hey calm down lol look at my post #12 I've grasped it lol

 

[shanky887614]

you really want to do this?


mcs guide


as I said..... kinda ****es me off the huge number of sparks seem to not be able to grasp this fairly basic concept for solar PV installations really. It's right there in plain english in the guidance they're all supposed to follow as well as in the inverter manufacturers instructions. It's really not that difficult a concept to grasp, and yet probably at least half of all solar PV systems have been installed with this wrong and will be more prone to over voltage trip out issues as a result.

Probably stems from apparently being qualified after attending a basic 3 day course mostly led by instructors who've only got the most basic grasp of the subject themselves I suppose, but it's still right there in all the guidance and instruction manuals.

eta - plus the financial losses to the customer.

get down off your high horse and finish the rest of the paragraph, it says in black and white it doesnt matter if you dont get 1%

 

[Gavin A]

get down off your high horse and finish the rest of the paragraph, it says in black and white it doesnt matter if you dont get 1%

does it really?

it says it's recommended, gives clear reasons why it's recommended, but gives allowances for this not being achieved in larger installations where it's not practical.

in a domestic installation there's almost never a reason not to hit 1%, the price difference is negligible between 2.5mm2 and 6mm2 cable.

It really is basic stuff, and when someone's paying £5-6k for an installation scrimping on the cable to save £20 is pretty shoddy IMO.

 

[Gavin A]

Hey calm down lol look at my post #12 I've grasped it lol

that post wasn't aimed at you, it was aimed at the poster who'd decided to attempt to prove me wrong, which was pretty daft given the subject area.

 

[Leesparkykent]

When I used to fit pv for EDF their spec on the AC side is 4mm as standard anything over 8meters has to 6mm and so on to maintain under 1%

 

[Gavin A]

When I used to fit pv for EDF their spec on the AC side is 4mm as standard anything over 8meters has to 6mm and so on to maintain under 1%

yeah, 4mm2's not an issue for shorter runs, but most of the 2.5mm2 stuff seems to also be done by the companies installing in lofts, where it's usually a longer run even than that.

I find it simpler to only carry 6mm2 rather than trying to keep stocks of both 4mm2 and 6mm2 on the van, that way there's only the very occasional system on a mansion or something that needs a bigger csa.

 

[shanky887614]

if you work it out using bs7671 then 4mm is overkill using vd

mV/a/m x ib x L / 1000
2.5 twin is 18mV/a/m

so say 17amps for 4kw say 9m to the inverter

18 x 17a x 7m / 1000 =2.14v which is under 1%

 

[Gavin A]

if you work it out using bs7671 then 4mm is overkill using vd

mV/a/m x ib x L / 1000
2.5 twin is 18mV/a/m

so say 17amps for 4kw say 10m to the inverter

15 x 17a x 10 / 1000 =2.5v which is 1-1.5% depending on supply voltage

now as

where did the 15 come from at the start of that? surely that should be 18 x 16A x 10 / 1000 = 2.88V? which is 1.25% of the nominal voltage.

The problem is, if the supply voltage is coming in at say 251, then that 2.88V will push the inverter over the 253V nominal voltage limit, and with several inverters will cause nuisance tripping on the 10 minute average 253V setting, whereas if it had been 6mm2 the inverter wouldn't be tripping out.

The instant trip settings are up at the 263-264V range, so are reached more rarely, but can be an issue where multiple pv systems are installed on the same transformer

The a.c. cable connecting the inverter(s) to the consumer unit should be sized to minimise voltage
drop

The guidance is to minimise volt drop, I really don't see that 2.5mm2 meets that requirement other than where the inverter is installed at the grid connection point.

1% should be top end, not 1-1.5% is ok in a domestic setting.

 

[shanky887614]

where did the 15 come from at the start of that? surely that should be 18 x 16A x 10 / 1000 = 2.88V? which is 1.25% of the nominal voltage.

The problem is, if the supply voltage is coming in at say 251, then that 2.88V will push the inverter over the 253V nominal voltage limit, and with several inverters will cause nuisance tripping on the 10 minute average 253V setting, whereas if it had been 6mm2 the inverter wouldn't be tripping out.

The instant trip settings are up at the 263-264V range, so are reached more rarely, but can be an issue where multiple pv systems are installed on the same transformer


The guidance is to minimise volt drop, I really don't see that 2.5mm2 meets that requirement other than where the inverter is installed at the grid connection point.

1% should be top end, not 1-1.5% is ok in a domestic setting.

there are usually multiple settings for each region so you just need to selet the right region for that voltage range if its that close.

done it before and it wont cause nuisance tripping, how can it. a 17amp load on a 20amp+ breaker

 

[Gavin A]

oh, I see you've changed the distance to make your point valid.

Not sure how many cables you've strung from the CU to the inverter in a loft, but you'll almost always come up short at 7m IME.

besides, the requirement is to minimise the volt drop, not to use the smallest CSA cable you can possibly get away with based on the current carrying capacity.

 

[Gavin A]

there are usually multiple settings for each region so you just need to selet the right region for that voltage range if its that close.

done it before and it wont cause nuisance tripping, how can it. a 17amp load on a 20amp+ breaker

nuisance tripping of the inverter not the MCB.

so you mean you're not selecting the G83 settings on the inverter? or are you raising the reference voltage from 230 to 240V?

interesting, and likely against the G83 regulations unless you have advance permission from the DNO. But I'd have to ask, why not install the correct cable size in the first place?

 

[tom262]

this is all good and all that but its gone way off subject, how much do you guys charge??