new model sma 3600tl- 2

[gordysolar]

Does this inverter require 100ma type b protection and also array earthing back to a rod what size earth wire needed?

 

[SolarCity]

No, it doesn't require type b protection (unless the route of your wiring dictates otherwise) and it will need earthing back to either an earth rod or the MET. We use 10mm earth.

 

[anthanth]

So if it does not require type b rcd then a type A rcd must be fitted - according to the criteria for selection rcd published by sma?? correct??

 

[pwboston]

IF it needs an RCD then a type A as you have read yes.

 

[anthanth]

ok, thanks for that. so if no rcd is needed, as the cable is not burried more than 50mm etc then it it could be wired into main db in house with main switch. (60947-3)

is that all correct?

 

[Gavin A]

just a point on this inverter that SMA don't seem to be publicising.

It's fanless, relying entirely on convection cooling up it's heat fins on the back to cool it.

I can't entirely decide if this is a positive thing or not, but it at least means there's no fan to go wrong on it. I'd be more wary though about overloading it in situations where the air temperature is likely to get warm.

 

[docka]

So even on a TT supply this inverter is ok on a standard RCD??

 

[Vegelen]

It's fanless, relying entirely on convection cooling up it's heat fins on the back to cool it.

I can't entirely decide if this is a positive thing or not

As long as the solar system has been appropriately designed and not overloaded, it shouldn't be a problem.
These units are well built and have decent heat sinks on the back to remove heat.
Im not sure if i'd have them installed in a confined roof space in Greece, but the UK should be fine.
Remember that these SMA TL Inverters also have a relay inside which can turn a load on under certain conditions.
If you are worried about your loft getting hot and the inverter overheating why not install a fan on a seperate circuit, to turn on under a predifined solar load or inverter system temperature.
This relay could also be used for alternative reasons, i.e turning on an immersion circuit under certain inverter power output conditions.

 

[pwboston]

The working parameters of all SMA inverters are large in regards to temperatures.

 

[Gavin A]

The working parameters of all SMA inverters are large in regards to temperatures.

they're not immune to the basic laws of the speed of capacitor degradation relative to operating temperature though, so better to keep them cooler if possible.

As convection currents are entirely reliant on the temperature difference between the ambient air and the heat fins I can see the ambient air temperature being more important here than in a system that has the option of switching a fan on to boost the air flow across the fins. I could be wrong, but this would be my working assumption until someone shows me that I'm wrong.

 

[Gavin A]

If you are worried about your loft getting hot and the inverter overheating why not install a fan on a seperate circuit, to turn on under a predifined solar load or inverter system temperature.
This relay could also be used for alternative reasons, i.e turning on an immersion circuit under certain inverter power output conditions.

you do realise I'm an installer, not talking about my own system?

and yes, we've installed 15 of them this month, and about 60-70 4000TL's so I'm well aware of their capabilities. i was just pointing out about the fanless nature of the 3600TL as I've not seen it publicised anywhere and it was a wee bit confusing when we opened up the first one to find a missing fan.

 

[Vegelen]

you do realise I'm an installer, not talking about my own system?

and yes, we've installed 15 of them this month, and about 60-70 4000TL's so I'm well aware of their capabilities. i was just pointing out about the fanless nature of the 3600TL as I've not seen it publicised anywhere and it was a wee bit confusing when we opened up the first one to find a missing fan.

Yes I accept your point.

Some TL's have no fan, some do and the only indication SMA provide is in the small print.

I prefer fanless unit's- 1 less thing to go wrong and less energy wasted.

 

[SolarCity]

I disagree that inverters are okay to fit in lofts in UK. Anyone that has ever worked in a loft space in the summer will tell you that the heat in there can be utterly unbearable.

We only fit in lofts if all other options have been exhausted.

One point I would like to make is regarding fans and air bricks in loft spaces. We've cut 4inch holes into the gable end next to the inverter and fitted grills. It doesn't seem to be a good idea. We've done this twice and on returning to the sites we have found large dust build up on the fans in the inverter. If you're going to do it, avoid inverters with fans.

 

[Gavin A]

It does really depend on the other options available, but there are some mitigating factors here, such as the panels themselves shading the majority of the south facing roof aspect, which is going to reduce the summer time loft temperature to some degree, and well ventilated loft spaces - if it's possible I do like to add a vent tile or 2 (or more in some circumstances), particularly near the ridge if the loft doesn't seem to have much ventilation.

Another thing worth considering if you have to mount in the loft is the temperature difference between the bottom and top of a loft in summer, which I've measured at around 6-10 degrees (bored and very hot when doing solar water heating with temp sensors to hand). So putting it low level could seriously increase the life of the inverter... a point I had to make with a customer who insisted on putting it in the loft, but wanted it mounting right in the apex of the ridge over his header tank.

 

[liquidity]

they're not immune to the basic laws of the speed of capacity degradation relative to operating temperature though, so better to keep them cooler if possible.

As convection currents are entirely reliant on the temperature difference between the ambient air and the heat fins I can see the ambient air temperature being more important here than in a system that has the option of switching a fan on to boost the air flow across the fins. I could be wrong, but this would be my working assumption until someone shows me that I'm wrong.

It's like the radiator in your car - when the weather is cold the temperature differential between the radiator temp and the ambient air provides sufficient cooling but in the summer the reduced differential isn't enough so a fan is used to increase the air flow.