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A close call! | 12 comments (12 topical, 0 editorial)

Re: A close call! (3.00 / 0) (#2)
by wooferhound (tim((NoSpamAt))wooferhound.com) on Sat Aug 2nd, 2008 at 01:54:49 AM MST
(User Info) http://wooferhound.com

I am using the same 60amp terminal strips in my battery fuse panel

I noticed that if I put a small wire under the screw that it was possible to twist the screw past the threads in the terminal strip because of the small wire sizes. so I strip the wire twice as far as normal and then fold the wire over double before putting it into the terminal and tightening it down. for really small wire I will triple or quadruple fold the wire to get the thickness of the wire big enough to get a good tight connection of the screw.

And speaking of fuse panels. If you don't have everything fused that connects to your battery, then you are just waiting on your first battery electric fire. Also I am seeing a failure mode in those terminal strips that isn't really safe.
W o o f -={(

Re: A close call! (3.00 / 0) (#3)
by rossw on Sat Aug 2nd, 2008 at 02:04:38 AM MST
(User Info) http://house.albury.net.au/

Yes, the cable I had going in there was 2.5 sq mm (only a short length, about 8"), and I had twisted it and folded it over. I'm well aware of the issue there, and yes, it was done up tight.

I noticed on one of the photos, it looks like the copper itself has oxidised in the connector - but was that cause, or effect? (of getting hot?!)

I just don't know what caused it. Its the first time I've ever had a failure like that and I've been doing this stuff now for 40 years.

As for fuses - main fuses to protect against catestrophic failure, sure. But they're some hundreds of amps - but then the battery leads are 35 sq mm too.

The PV arrays have protection.

I don't WANT to fuse between the rectifier and the batteries - if the fuse blows because of high turbine current - it means I've got a gale, and I don't want it running open circuit.

I've seen WAY more fuse failures over the years than I've seen these connectors fail, I guess what I was trying to say is to fellow RE folk, to keep your eyes open for anything that changes and investigate it.

(And do you REALLY think it's necessary to put a fuse in each and every wire that goes to each and every component - either side of every connector, and both ends of every cable "just in case"?? Sure, if we had infinite financial resources... or it was in a spacecraft...)

[ Parent ]

Re: A close call! (3.00 / 0) (#4)
by Flux on Sat Aug 2nd, 2008 at 02:27:56 AM MST
(User Info)

I have seen a few of these failures and some have been where there was no obvious cause.

Low voltage systems seem worse for it and the consequences are worse as the added resistance often prevents fuses from protecting these situations.

I agree that keeping an eye on it is about all you can do and it serves as a good reminder never to mount any form of connector on wood or other combustible things.

Even bolted or crimp connectors are not foolproof, once resistance develops the whole thing self destructs fairly rapidly.

Flux

[ Parent ]

Re: A close call! (3.00 / 0) (#11)
by acapulco (thatskankystuff{at}hotmail) on Sun Aug 3rd, 2008 at 09:57:24 PM MST
(User Info)

I have 60wat panels x 4 at 24volt and 8 x T-105 bank

My inverters have 20amp inline auto type fuses and I just put the same type of 20 amp fuse on the wire from the panels to the batteries.

I have never had any problems in 5+ years but system was 12 volt but same bank and panels and same inverter capacity just 12volt. I have just now today changed the setup from 12 volt to 24 volt.

Am I just lucky to not have trouble or is that adequate fusing?

Do I need more/bigger/better fusing?

You now have me worried to sleep maybe I'll make a big shutoff to switch at night/ nobody home. If only i had clue where/how big etc

pls advise
Ian, AUSTRALIA.*OFF-GRID*.RE:2X 4xT105@24volt. IN:4X60wattPV,backup:Genset/charger24v@10amp cont. OUT:Mod.Sine Inverters: 1500w cont/4500w/2000w & 350w.
[ Parent ]

Re: A close call! (3.00 / 0) (#12)
by wooferhound (tim((NoSpamAt))wooferhound.com) on Mon Aug 4th, 2008 at 04:37:45 AM MST
(User Info) http://wooferhound.com

You should have fuses very close to the battery to protect the batteries and wiring from from short circuits and equipment malfunctions. Without fuses the wire becomes the fuse and the insulation becomes Fire.

W o o f -={(

[ Parent ]

A close call! | 12 comments (12 topical, 0 editorial)

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