Power Upset on New Years Day

[ruddycrazy]

G'day guys,

           Well around 7pm last night I was sitting back happily suckin back a few beers and chatting on irc when I asked my son to through the TV on. All of a sudden the power went out and my SA32 inverter refused to start backup.

Upon opening the fusebox I noticed the positive connections had shorted. It turned out the extra current needed finally made the connection give way and they went bang. I didn't get a pic of the burnout but here is the offending input fuse mount.

 

I decided the safest way was to make a new input junction block and only have the inverter positive lead and a bussbar on the fuse input. The junction block is 1/2" thick brass plate and the bussbar is 3mm brass plate. M6 holes were tapped in the block and for the bussbar I used 2 off M6 and a brass top securing plate.

I used some self amalgamating tape on the bussbar and put some pvc tape over the top, also around the junction I did the same. Once all the connections are in place i'll get some sealing compound and paint it on the junction to fully insulate it.

 

Above is the junction block all finished and working, as soon as I put the fuses back online the FM60 came back to life in sleep mode, then as soon as I turned on the pv it woke up and started charging again.

It just goes to show being complacent with RE can have major problems if connections aren't done properly. Hopefully this fix will be the end of murphy paying a visit with my house RE.

Cheers Bryan

[DamonHD]

Good fix.

I think that as we handle more RE power we have to be more careful...  In the summer I had my first bad contact overheat.  Luckily outside and did no harm.

Rgds

Damon

[SparWeb]

I'd like to understand your wiring more, if you don't mind Bryan.

It looks like you have a fuse on the negative and positive terminals leading to the battery.  Is that what I actually see?  Why did you do this?  I can guess at an added safety reason but if you can explain I'd like your take on it.

Why do you feel the need to thoroughly seal the junction block?  A plastic box would suffice.  I'm just thinking of the next time you have to change a wire (or add a panel) you have to chip away all the goop you've poured on it.

 

[ruddycrazy]

Hi Steven,

          The fuse box was part of the 25K solar package and was supposed to be a professional install. The fuses are re-settable 125 amp ones and I always wondered why they bothered doing both negative and positive.  As you can see the rats nest on the shunt the positive was the same. I'll be using the same terminal connections for each tapped hole and by painting the surface with the insulation paste will ensure the junction block is isolated from a possible short. The problem I would have with a box is critters will get inside and cause more problems. If I ever need to change a fitting after the goo goes on it will be a simple case of painting the new connection. The goo I'll be using is a commercial grade of liquid insulation tape. I suppose having an electrical wire wholesaler who also sells just about everything to do with motor re-winding does have it's benefits. As soon as the expiry date comes around on the Dow Corning etc stuff the rubbish bin is the back of my ute.

Cheers Bryan