Dometic RM7401L dc fuse rating???

[sshortcircuit]

On several occasions now I have found the dc fuse melted. From the manual it is 10 amp. Looking at the details within the fridge the element is described as 12v 130w which would result in a current draw slightly in excess of 10amps. I could increase fuse to 15amps but my concern is that the wiring may be inadequate for this current and the possible effects to the fridge pcb.

 

Can an expert please advise me what size the fuse should be.

 

My second thoughts are that the element is shorting out and I would ask if anybody has an idea of what the resistance should be.

[Robinhood]

.....somewhat intrigued by the mismatch in potential current draw and the rating of the fuse, I looked at the manual on the Dometic website.

 

There are many different versions (revisions) posted for the RM7401L but I sampled a few, and all had the installation instructions as set out in the picture below.

 

This should give you the required information on the fuse rating, (15 amp looks better) and a means of checking your wiring capability (I suspect the wiring 'run' will mean that 4mm squared will be sufficient).

 

Not sure which manual your 10 amp suggestion came from?

 

Edited to add:

 

BTW, what year is your Kontiki - the wiring diagrams are readily downloadable from the web, and the usual Swift provision for the fridge was a 15 amp fuse.

[sshortcircuit]

Thanks Robin. My Kontiki is 2005 and the fuse rating was taken from a Swift circuit diagram I had downloaded. Will up to 15amp once I have checked cable size. Thanks again.

[Robinhood]

sshortcircuit - 2012-07-28 12:16 PM

 

Thanks Robin. My Kontiki is 2005 and the fuse rating was taken from a Swift circuit diagram I had downloaded. Will up to 15amp once I have checked cable size. Thanks again.

 

.....in which case, I think the wiring diagram is this one (3rd diagram):

 

http://www.sargentltd.co.uk/Swift_Motorhome_schematics_2005.pdf

 

.....which shows the 15 amp fuse, and should reassure you that the wiring should be OK for this.

[sshortcircuit]

Having checked the small print it is 15A. Not sure how a 10A came to be in fuseholder but no damage done. Again thanks.

[sshortcircuit]

Changed to a 15A. Had a run today and after about 30 minutes fuse plastic has melted although blade shows no signs of heat. Perhaps because its a cheap fuse may now be the problem so will change for a quality unit for my return journey

[PeteH]

Hi

 

You have a Bad Connection or Joint somewhere in the circuit > If you are now blowing a 15amp fuse regardless of quality, I would suggest that you have a HIGH RESISTANCE wheresoever in your frig;

circuitry.

 

Increased resistance can be as simple as a Corroded connector at any point in the circuit including the EARTHING connection. In fact anything which increases resistance will cause the conductor to overheat.

 

Pete

 

 

[sshortcircuit]

No I am not blowing the fuse. As I said the fuseable link looks ok just the plastic that has melted. I always understood that increase resistance results in a reduction in current and hotspots created by a poor joint. When I get home I will check the complete circuit. Thanks for info

[Brian Kirby]

sshortcircuit - 2012-08-02 7:43 PM

 

No I am not blowing the fuse. As I said the fuseable link looks ok just the plastic that has melted. I always understood that increase resistance results in a reduction in current and hotspots created by a poor joint. When I get home I will check the complete circuit. Thanks for info

It may be that the fuseholder is the source of the problem. If the fuse is not blowing, but its plastic cover is melting, it is local heat, either due to load, or there is some arcing around the blade connections. Can you replace the holder?

[sshortcircuit]

Thanks Brian. I have moved to another fuseway with good tight connections and no arcing. will give another check though.