Solar panel circuit MCB size?

[netblindpaul]

This forum never ceases to amaze at the lack of understanding of some members, and their total denial when it comes to absolute engineering and scientific facts, and proven data.

 

[shanky887614]

same as isis solar and home sun apart from a lot of these were fitted with fronius inverters.

i thought some of the fronius inverters came with a 15 year guarantee?

 

[Gavin A]

dont forget that is internal temperature and the internals will hit 30oC quite easily inside the inverter so i doubt it would make a huge difference, throw as many charts at me as you like

I know, but the rate of cooling is directly proportional to the ambient air temperature.

I also know that we get virtually every job where the other companies quoting have opted to install the inverter in the loft when there was a cooler option available after we explain this point to them, particularly when the customer is more technically literate.

 

[Leesparkykent]

i thought some of the fronius inverters came with a 15 year guarantee?

yea i think so

 

[Gavin A]

i thought some of the fronius inverters came with a 15 year guarantee?

Fronius offers a 5-year manufacturer warranty on all inverters as standard. You also have the option of extending the warranty period to 10, 15 or 20 years. If a claim is made, Fronius bears the costs for original replacement parts, transportation and work undertaken. The extended warranty therefore protects against any fluctuations in price for the entire warranty period. In addition, free support is on hand from our competent and easy to reach hotline team for the entire duration of the warranty period.

but extended to 10 years as of 1st January apparently

 

[davesparks]

dont forget that is internal temperature and the internals will hit 30oC quite easily inside the inverter so i doubt it would make a huge difference, throw as many charts at me as you like

If the ambient temperature is less then the cooling of the unit will be more efficient,

 

[Gavin A]

So to conclude, the only reason not to put the inverter in the garage is some personal preference based on some vague fear of permanently live dc cables despite them being mechanically protected, and protected as an electrically separated circuit, and via RCMU and start up insulation resistance tests by the inverter.

The reasons in favour of it are based on sound scientific and engineering principles.

Think I'll stick to our methods and reasoning tbh.

 

[shanky887614]

no fear of live cables in walls, i would just rather put it in the loft unless customers wants it else where, let the customer choose where they want it

 

[Leesparkykent]

i understand your point on mechanical protection. but you keep banging on about start up insulation tests etc,this is irrelevant as the dc cables will still be live before, during and after regardless if the inverter starts up or not due to the insulation resistance test carried out by the inverter

 

[shanky887614]

i understand your point on mechanical protection. but you keep banging on about start up insulation tests etc,this is irrelevant as the dc cables will still be live before, during and after regardless if the inverter starts up or not due to the insulation resistance test carried out by the inverter

what are you talking about?

the panels themselfs are always generating electricity the inverter only checks for supply on ac and switches dc accordingly

 

[Leesparkykent]

what are you talking about?

the panels themselfs are always generating electricity the inverter only checks for supply on ac and switches dc accordingly

im quoting Gavin A. and this is my point exactly, Panels are always producing under daylight hence cables will always be live to dc isolator

 

[shanky887614]

im quoting Gavin A

ah i didnt see a quote

 

[Leesparkykent]

ah i didnt see a quote

sorry mate should of quoted Gavins post #67

 

[Gavin A]

i understand your point on mechanical protection. but you keep banging on about start up insulation tests etc,this is irrelevant as the dc cables will still be live before, during and after regardless if the inverter starts up or not due to the insulation resistance test carried out by the inverter

not irrelevant as if the inverter doesn't start up, or cuts out, then even on a TL inverter the circuit stays / becomes an electrically separated circuit with no potential to earth, so even if the cables did somehow get damaged and exposed despite the mechanical protection it would only be dangerous if someone actually grabbed hold of both + and - exposed cables at the same time, and only life threatening if they were holding one bare wire in each hand. ie they could touch the positive or negative cable while also touching an earth bonded radiator and feel absolutely nothing.

It'd also alert the customer to the fault as the inverter wouldn't be working, and the inverter would be somewhere easily accessible for them to notice this.

 

[driverman]

Read thread with great interest after my original question, thanks very much. I did chat to the customer last night and the reason for the inverter sited downstairs was..... cooler position.....which some you of mentioned earlier. If inverter sited elsewhere in the modern home and away from the mains position then I would of thought most homes would have 30ma RCD protection. Does that have any impact on solar panel installations?