Fuse sizing

[rmccabe20]

INTALLING 3 NO SUNNY TRIPOWER 15000TL, SUNNY TRIPOWER 10000TL / 12000TL / 15000TL / 17000TL. SMA UK VIA G59 PANEL, WHAT SIZE OF FUSE WOULD YU RECOMMEND AT AC MAIN PANEL BOARD

 

[rmccabe20]

MAX AC OUTPUT OF INVERTOR IS 24A x 3 = 72A , IS THIS THE RIGHT WAY TO WORK THIS OUT , WAS THINKING 80/100A , supply cable 35mm XLPE/SWA

 

[Worcester]

Supply cable will depend upon current and actually the critical factor will usually be the 1% voltage drop.

Normally on 3 x 1500TL's we'd go for 80A.

Why do you need a G59 panel? They are already certified to G59... What has your DNO said?

 

[jason121]

may I ask what is your trade. These can be worked out easily if you know your job well.

 

[BruceB]

OP, I do recommend you read the installation manual, which is downloadable. It makes clear that each inverter must be on its own mcb, and gives you a recommended size, and discusses rcds....etc, etc. One mcb covering a number of tripowers is not sufficient, assuming that is what you were suggesting.

 

[rmccabe20]

A g59 panel was specified for the job, this panel also provides us with 4 pole isolation and 3 seperate 40a tp mcb s to supply each invertor, volt drop is a big concern for me , the job was not designed by me , 100m with 35mm 4 core

 

[Worcester]

Where's the G59 relay going? at the far end of the 35mm2 cables? I guess not if the same board has the mcb's in. Unless you are running a remote sensing head for the g59, and putting the relays in the your voltage drop is too great, so you'll need to go up to 50mm2 to get below 1%.

If you accpet the greater voltage drop - what are you going to configure the 1500TL's to ? would be cheaper to install 50mm2 and through away the G59 relay...

Sounds like it needs designing properly.

Also you only need 32A tp MCB's

 

[rmccabe20]

Supply cable will depend upon current and actually the critical factor will usually be the 1% voltage drop.

Normally on 3 x 1500TL's we'd go for 80A.

Why do you need a G59 panel? They are already certified to G59... What has your DNO said?

Although many inverter manufacturers make declarations to state that there inverters will trip out under the parameters set out in G59-2 if the DNO insists on witnessing this, there is no way to demonstrate this without invalidating the inverter manufacturers warranties. If the G59-2 relay is fitted an experienced tester can easily connect the specialist test equipment & prove the installation will trip under all the conditions set out on page 3 services. This will then satisfy the DNO that there network will be protected & will not affect the supply voltages that they have to deliver to other users of the substation that the generator is connected to.

 

[Worcester]

Are the DNO insisting on witness testing?
So they reckon SMA's G59 certificate is worthless?
Even then there are people that will do the proof testing for a fraction of the cost of installing a G59 relay.

Litlle knowledge - dangerous thing.

Someone is overselling something me thinks...