What makes a better circut protection device?

thebigphish · Post by **thebigphish** » Mon Mar 15, 2004 10:42 pm

Ok, this is for all of those who are familiar with large, distributed power distribution systems in various vehicles...

When you fuse that BATT+ for your power panels, what do you use? replacable high amp fuses, circut breakers, fusable links (i know ONE who does)?

i'm interested to hear what y'all do...

007 · Post by **007** » Mon Mar 15, 2004 10:58 pm

Circuit breakers are ok when not used in a high heat environment, since the ambient heat will de-rate the circuit breaker.

High current fuses are my fav...

jim · Post by **jim** » Tue Mar 16, 2004 6:34 am

Circuit breakers must be ambient temperature AND in a dry location, since most aren't waterproof. Also, breakers have a "delay factor" built into them. I'll never use an auto-reset on a main feed. If it opens, there's a real problem and shouldn't close again.

I prefer to use the inline wafer fuse with the ring terminals on its cable soldered and adhesive shrink tubed. Single feed is simple, provides the most current (compared to small individiuals) and by far, the most reliable.

Fuse link also works well and is inexpensive. It acts like a breaker with its "delay". After all, GM, Ford and Mopar use them all over their feeds. In fact, they also use them to protect the OEM police power mains going into the distribution box. Trying to find a good source for fuse link is the problem, however. You can do 10 installations with fuse link for the same price as one TST or Buss mains breaker.

FresnelZone · Post by **FresnelZone** » Tue Mar 16, 2004 9:53 am

I much prefer using a normal fuse across the primary feed for power. In the event there really is a problem, the chances of the officer telling you about it if it just goes out then resets 10 seconds later is pretty slim compared to a complete loss of lighting.

I've seen wiring that has melted, arched and caused flames because either the circuit breaker failed under heat and moisture (under hood application) or the circuit breaker was way over rated for the circuit. By the time the circuit breaker finally completely opened the circuit, the damage had been done. Had it been a fuse or a fusible link, a bit of charring could have been avoided, along with the several thousand dollars of insurance work (wasn't our shop that did the install)...

commtek · Post by **commtek** » Tue Mar 16, 2004 1:28 pm

I've always used Jim's methods and techniques. Wafer fuses work well for protecting primary feeds. I've seen too many problems with rows of circuit breakers under hoods of public safety vehicles.

c17loadsmasher · Post by **c17loadsmasher** » Wed Mar 17, 2004 3:43 am

Maybe not related 100%...but any thought on 'load managers?' Personally, I hate 'em.

jim · Post by **jim** » Wed Mar 17, 2004 2:33 pm

I won't do a fire vehicle w/o a load manager. If set up PROPERLY, they are a great thing. Too bad most are a effed up when installed.
Nobody takes the time to set the loads up properly, then you have scene lights or other critical items shutting down.
Most don't realize that you can run the HVAC through the managter and save a TONS of current.

thebigphish · Post by **thebigphish** » Wed Mar 17, 2004 2:46 pm

jim wrote:Nobody takes the time to set the loads up properly, then you have scene lights or other critical items shutting down.

know that feeling, one wanker wired a bus so that the pt compartment lights would go off on high loads....but damn it, those cabinet lights would stay on!

c17loadsmasher · Post by **c17loadsmasher** » Wed Mar 17, 2004 4:29 pm

Sounds like our attack pumper. Scene lights go out randomly, half the warning lights drop out. Good thing it was wired with an override switch.

nmfire10 · Post by **nmfire10** » Wed Mar 17, 2004 5:20 pm

I've had the load manager kick in once on our new tanker. Between that and the high-idle going up to about 3,000RPM, it was interesting.

c17loadsmasher · Post by **c17loadsmasher** » Thu Mar 18, 2004 5:34 pm

I've been pondering just ripping it out, but...ehh it was wired f-ed up from the factory, so Lord only knows what else may break (or get fixed) by some rough love.

apco25 · Post by **apco25** » Thu Mar 18, 2004 5:40 pm

I like the BIG HI-AMP fuses and holders. That is what is protecting the front and rear feeds on my rig, with of course each item having its own fuse at the distribution block.

I've used the manual reset breakers in the past, but no longer due to the reasons listed above.

kb9suy · Post by **kb9suy** » Mon Mar 22, 2004 9:35 pm

One of our engines is all circuit breakers. its real joke. I dont do the light installs some one else does. I just through my knowledge around when they cant figure out whats wrong. any way one day we were doing some live burns an the engine had been pumping for a few hours. well as you all know they get hot. well we went to try an get it back in to pump to do a little preventive rekindle maintnence an we couldnt get it into pump. so we were going back to the station an went to back in hit the lights nothing went one. hmmmm took the cover off were all those circuit breakers were all fried. man that would of looked good. Local fire departments fire engine goes up in flames.

What makes a better circut protection device?

What is your favorite BATT+ protector?

What makes a better circut protection device?