Why trailers burn

[lewster]

Originally Posted by tpi

Do you think a big 100 or 150 amp fuse right at the battery would be a good idea?

You need to gauge the size of the fuse to the wire that you have connecting your battery bank to the trailer. 100 amp would probably be a little excessive for the 6AWG that IIRC is used in Airstreams, but 110 amp is the lowest rating available for a class 'T' fuse, which is the device I would recommend.

[Jammer]

Originally Posted by 2airishuman

?? it seems u asked pretty much the same question 366 days ago...

This time I'm hoping for more insightful answers.

Originally Posted by overlander63

For those interested, here is a picture of the "flammable" connector:

The transfer case in my TV is made out of magnesium, as are many. I wonder how great the hazard actually is although certainly cutting and grinding operations do pose a risk.

Originally Posted by lewster

<<class T fuses instead of cheap automotive breakers in the battery line>>.

Lewster I find your post extremely insightful. It had not occurred to me that the self-resetting automotive circuit breakers might be prone to failing closed, but it makes sense that they would in the event of a short.

I have the stock automotive breaker and will add its replacement to my list of things to do.

I would suggest a Class J fuse for this application rather than a class T fuse. Class J fuses are available in a wider range or ratings from 1 amp to 600 amps, with 5 different physical sizes depending on current rating. Although sold primarily as an AC fuse, they are rated by the manufacturer for use on DC circuits up to 300 volts.

Here's a link for the fuses and holders:

Class J (1-200 Amp) Fuses & Holders Products

[heslinhotel]

Had one on the 1978 31' Soverign International I had. I replaced it due to the round pins. Put in a new 7 pin flat so that I could replace 7 wire umbilcle to TV that was very stiff. I had no idea they were magnesium. Still have the old one, might make a good demo to warn others of the potential dangers. Thanks for the heads up.

[lewster]

"..............Lewster I find your post extremely insightful. It had not occurred to me that the self-resetting automotive circuit breakers might be prone to failing closed, but it makes sense that they would in the event of a short.

I have the stock automotive breaker and will add its replacement to my list of things to do.

I would suggest a Class J fuse for this application rather than a class T fuse. Class J fuses are available in a wider range or ratings from 1 amp to 600 amps, with 5 different physical sizes depending on current rating. Although sold primarily as an AC fuse, they are rated by the manufacturer for use on DC circuits up to 300 volts.

Here's a link for the fuses and holders:

Class J (1-200 Amp) Fuses & Holders Products"



Jammer,

I had considered these, but I could not find any specs on their maximum amperage thresholds. If you get a huge DC spike like happened in this poor guys SOB that fused the contacts of his automotive-type CB, it can also 'fuse' the contacts within the fuse and allow the current to pass thru. The 'T' type can withstand spikes over 10,000 momentary amps, which is why all of the inverter manufacturers recommend them for protecting the DC feeds from the batteries to their inverters.

I'll have take a closer look at the 'J's.

[overlander63]

Originally Posted by Jammer

I wonder how great the hazard actually is although certainly cutting and grinding operations do pose a risk.

This would probably be about the only time of hazard. In the case of the photo above, the mounting bolts are very rusty, and may need to be cut off. In that case, caution should prevail.

[Jammer]

Originally Posted by lewster

Jammer,

I had considered these, but I could not find any specs on their maximum amperage thresholds. If you get a huge DC spike like happened in this poor guys SOB that fused the contacts of his automotive-type CB, it can also 'fuse' the contacts within the fuse and allow the current to pass thru. The 'T' type can withstand spikes over 10,000 momentary amps, which is why all of the inverter manufacturers recommend them for protecting the DC feeds from the batteries to their inverters.

I'll have take a closer look at the 'J's.

They are typically rated at 100,000 interrupting amps (100 kia) DC although not all manufacturers publish a DC rating.

CLASS J FUSES: BUSSMANN, FERRAZ SHAWMUT, AND LITTELFUSE

I don't know what the deal really is with the class Ts. Most of the ones sold through industrial suppliers specify a 100 kia or 200 kia rating which is what I would expect. The boating and rv places sell what appear to be identical fuses with lower ratings. The class Ts are supposed to be fast acting to protect semiconductors but even a slower acting fuse will prevent a fire.

[Frank's Trailer Works]

Originally Posted by overlander63

For those interested, here is a picture of the "flammable" connector:

Man, I love learning new things. The last one of these I replaced was held on by rust bolts. I cut them with my grinder. I had intended to use it again, but it fell to the ground and the lid broke off. I guess I was very lucky to not get ignition. I ended up with a box of old inlets and umbilical ends from a friend. When I moved my shop I tossed the box thinking I would never use them. Had I know, I would have saved them for campfire shenanigans.
Terry, sorry you had to learn this lesson the hard way and thank you for sharing....

[AIR-Quarius]

Ours is a 70' model but I never speculated the power cord at the front hitch. This cord (mine) is black.

[overlander63]

Originally Posted by 62overlander

Man, I love learning new things. The last one of these I replaced was held on by rust bolts. I cut them with my grinder. I had intended to use it again, but it fell to the ground and the lid broke off. I guess I was very lucky to not get ignition. I ended up with a box of old inlets and umbilical ends from a friend. When I moved my shop I tossed the box thinking I would never use them. Had I know, I would have saved them for campfire shenanigans.
Terry, sorry you had to learn this lesson the hard way and thank you for sharing....

Originally Posted by Airbuckled

Ours is a 70' model but I never speculated the power cord at the front hitch. This cord (mine) is black.

The end in question is grey. Looks like plastic, feels like metal. Somewhere I have a photo of the one I toasted while it was burning. Yes, I took the photo after I called the fire department... If I can find it, I'll post it.

[NevadaGeo]

Originally Posted by Jammer

This time I'm hoping for more insightful answers.



I have the stock automotive breaker and will add its replacement to my list of things to do.

I would suggest a Class J fuse for this application rather than a class T fuse. Class J fuses are available in a wider range or ratings from 1 amp to 600 amps, with 5 different physical sizes depending on current rating. Although sold primarily as an AC fuse, they are rated by the manufacturer for use on DC circuits up to 300 volts.

Here's a link for the fuses and holders:

Class J (1-200 Amp) Fuses & Holders Products

Hey guys, we really appreciate the hi class information, but J's and T's just don't mean much to me....maybe a couple words to us earthlings what they mean, so if I need to ask an electrician, I might not get a D.

[Wsmith]

I just had a electrical fire in my '85 Excella today. I had been in the trailer working on a restoration of floor. I took a small brake to look for some parts online and cool down. About twenty minutes later walked out and fire was burning through the bedroom vent. I got it put out before it did tons of damage. I have some blistering on the interior plastic coating within 2' of the light fixture. Light plastic smoke throughout the trailer.

I don't know if fire started from the electronic ballast for the florescent light or if it was the fan motor but in either case it did not trip the circuit..

As soon as I get the floor section back down I will be replacing every D/C breaker in the panel. It looks like they are riveted into the breaker panel.

[NevadaGeo]

The rotary light switches on the ceiling light/vent fixtures get old and arc-ey, folks like to swap them out with new ones but I wouldn't think an '85 would be doing that yet.

[Wsmith]

Originally Posted by NevadaGeo

The rotary light switches on the ceiling light/vent fixtures get old and arc-ey, folks like to swap them out with new ones but I wouldn't think an '85 would be doing that yet.

Switch is the new style and was about 12 inches from the light. I still haven't taken the assembly out to inspect it closely. Hopefully I will be able to detect where the arching.
I am trying to decide what fantastic fan to install in its place.

[Secguru]

I never fail to be amazed at 2Air's thoughtfulness, research, intelligence, diligence, educational replies, his considerate approach and kindness.

You are my hero!

[Frank's Trailer Works]

He's very lucky that you perceive him that way...

[Soyboy]

Frank: sorry to see the photos of Anna. Bummer. Hope you are able to keep it original.

Fuses:

This was the first time I saw this thread. FWIW, on my trailer I run a marine style Blue Sea terminal fuse on the battery post. That way I have no "unfused" lines running into my trailer. The fuses are not cheap, but they are fully enclosed etc. IIRC they have a 10,000 amp interrupt rating.

I have recently purchased an AM solar setup, although they have an upgrade to a high quality circuit breaker (I think it's one of these Note pdf file) I got the standard fuse holder. I am going to order that circuit breaker today. BTW it has a 5000 amp (at 12V) interrupt rating. Pretty stout and worth the bucks. I think I am also going to look under the couch to see if anything else needs an upgrade fuse/breaker wise.

This stuff kind of makes me wonder why AS doesn't make more two door models. Many moderate and larger style SOBs (even cheapo models) have two doors. A huge safety feature in my book. Seems like it should be some sort of code requirement. A lot of folks would have a hard time getting out the window. This was something I use to think about when we contemplate getting a 5th wheel years ago, how do you get out and on to the ground safely from the bedroom in one of those. Especially when you think a lot of folks that own them are older and lets face it, look around the campground, out of shape.

If there is a fire, getting everyone out safely is the #1 priority. The trailer is replaceable.

Good Thread.