Fuse melting.

[Dazza 6863]

Afternoon funsters,
driving back from Knaresborough yesterday I could smell some burning plastic and after pulling over and checking I found a fuse slightly melted into the fuse holder in the ec600 power supply, it is fuse 13 on the list and powers the fridge D+. looking for answers to why this would happen and recommendations to find a repair
kind regards Darren

 

[Boringfrog]

Was it a nice tight fit in the holder?

 

[rosalan]

If it is caused by the fridge, is the fridge still working? Is the van new? Could the wrong value fuse have been fitted?

 

[Dazza 6863]

Was it a nice tight fit in the holder?

yes it was actually stuck in and a piece of the holder is now stuck to the fuse

 

[Dazza 6863]

If it is caused by the fridge, is the fridge still working?

yes, the fridge works on gas, 240 and 12v when I put a new fuse in?

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[rosalan]

The fault, I assume, is on the mains circuit and will only be powered up when on hook-up. Is there any chance that the power supply could be involved in your problem.

 

[rico]

Had the same problem. Spoke with Sargent and according to them Swift have fitted a 15 amp fuse when it should be 20 amp. Following their advice and fitted 20 amp. No further problems at the moment!!
Attached picture of fuse removed and still works

 

[dash300]

Had the same problem. Spoke with Sargent and according to them Swift have fitted a 15 amp fuse when it should be 20 amp. Following their advice and fitted 20 amp. No further problems at the moment!!
Attached picture of fuse removed and still works

Another great advert for Swift!

 

[Dazza 6863]

The fault, I assume, is on the mains circuit and will only be powered up when on hook-up. Is there any chance that the power supply could be involved in your problem.

I think this fuse only powers when driving, I stand to be corrected though.

 

[Raul]

A fuse melting but not going pop in the first place to open the circuit, indicates a bad loose connection rather than undersized fuse. If it was the fuse to small, it will just simply pop open but not melt, loose connection high resistance caused the melt.

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[Dazza 6863]

Another great advert for Swift!

A fuse melting but not going pop in the first place to open the circuit, indicates a bad loose connection rather than undersized fuse. If it was the fuse to small, it will just simply pop open but not melt, loose connection high resistance caused the melt.

I've checked where I can and everything looks ok and all the rest of the fuses are ok, just worried about changing the fuse and it catching fire.

 

[rico]

Speak to Sargent technical to clarify advice. This is not the first issue I have had with this type of control box in four years of use.

 

[NicM]

yes it was actually stuck in and a piece of the holder is now stuck to the fuse

Just because it had melted on to the fuse box and was hard to get out does not mean it is a good fit into the terminals.

 

[autorouter]

powers the fridge D+. looking for answers to why this would happen

The cause is probably contact resistance. When current (amps) flows through the contact area, the normally tiny resistance results in a normally tiny generation of heat. If the contact area is less than ideal, it will have a slightly larger resistance, so more heat is generated. This often has a snowball effect, ie the heat increases the contact oxidation, so the resistance increases even more, so it gets even hotter.

This is probably not the fridge D+, which is a low-current control signal. It's probably the supply to the fridge 12V heater element, which takes a lot of power, maybe 15A, which is getting near the limit for this type of push-in contact. It would be the first one to show symptoms if the contacts are not 100% perfect.

You could try a new fuse, and push it in and out a few times to try to rub off the oxidation. Also perhaps the receptacle may be a bit mis-shapen, so maybe try to squeeze it so it grips tighter.

 

[Dazza 6863]

Just because it had melted on to the fuse box and was hard to get out does not mean it is a good fit into the terminals.

Good point Nic, unfortunately, I cant check that particular fuse but I have inserted another fuse to check if it sits in tightly and it feels like it's tight, and the fridge works on 12v 240, and the gas when I check but for safety, I have removed it until I get answers from Sargent. i have just checked on the Sargent website and a power supply repair is £156.59 with a five-week turnaround I have also taken extended cover through my dealership with MB&G so hopefully, it is covered with them.

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[Gellyneck]

Had the same problem. Spoke with Sargent and according to them Swift have fitted a 15 amp fuse when it should be 20 amp. Following their advice and fitted 20 amp. No further problems at the moment!!

Not the same marque but our 2013 AT has a 20A fuse for the Fridge D+ (Dometic RMD8555) albeit in the EM40 interface fuse box.

 

[Dazza 6863]

The cause is probably contact resistance. When current (amps) flows through the contact area, the normally tiny resistance results in a normally tiny generation of heat. If the contact area is less than ideal, it will have a slightly larger resistance, so more heat is generated. This often has a snowball effect, ie the heat increases the contact oxidation, so the resistance increases even more, so it gets even hotter.

This is probably not the fridge D+, which is a low-current control signal. It's probably the supply to the fridge 12V heater element, which takes a lot of power, maybe 15A, which is getting near the limit for this type of push-in contact. It would be the first one to show symptoms if the contacts are not 100% perfect.

You could try a new fuse, and push it in and out a few times to try to rub off the oxidation. Also perhaps the receptacle may be a bit mis-shapen, so maybe try to squeeze it so it grips tighter.

Thank you,

 

[the1andonly]

12V FIDGE supply problem get a european van they dont have them? My 2017 Rapido had a fridge recall before it had been sold.
The 30A fuse had to be replaced by a 20A and a little sticker attached to show modification had been carried out. It had been spec'd to 30A but incorrect gauge wire used, so change of fuse.

 

[xsparks]

I had this problem with mine. The fuse rating was borderline capacity. Alongside I had a spare way that was unused so I moved the wire leaving the block for the fridge to the new way and increased the rating to 20a. Some fuses that you can buy are often of poor quality and I would advise against buying from cheap outlets such as Poundland. This is false economy in my opinion.

 

[pappajohn]

Most likely cause... Cheap crap Chinese fuses.
A quality fuse should blow long before it melts.

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[Dazza 6863]

I had this problem with mine. The fuse rating was borderline capacity. Alongside I had a spare way that was unused so I moved the wire leaving the block for the fridge to the new way and increased the rating to 20a. Some fuses that you can buy are often of poor quality and I would advise against buying from cheap outlets such as Poundland. This is false economy in my opinion.

Most likely cause... Cheap crap Chinese fuses.
A quality fuse should blow long before it melts.

Fuses are the ones that came with Van from new, bought my spares from Halfords but have not had to use them until now.

 

[autorouter]

The cause is probably contact resistance.

Looking at the photo, it looks more like the fuse itself has heated up, not the contacts. That ties in with what rico said, that it should be a 20A fuse, not a 15A. If the current was about 15A then the fuse would not blow, but would probably get quite hot. It's usually recommended to use a fuse that's 20% more than the usual amps, also making sure the wiring can handle this.

 

[Dazza 6863]

Looking at the photo, it looks more like the fuse itself has heated up, not the contacts. That ties in with what rico said, that it should be a 20A fuse, not a 15A. If the current was about 15A then the fuse would not blow, but would probably get quite hot. It's usually recommended to use a fuse that's 20% more than the usual amps, also making sure the wiring can handle this.

I'm not very good with electronics, all I know is the power unit was already fitted in the motorhome when we bought it 3 years ago, how would I find out if a 20amp fuse would be safe?
Thanks again for the advice

 

[NicM]

I'm not very good with electronics, all I know is the power unit was already fitted in the motorhome when we bought it 3 years ago, how would I find out if a 20amp fuse would be safe?
Thanks again for the advice

If you are unsure of sorting it your self then you need to have it looked at by an auto election, as I think you said were.

 

[Richard n Ann]

I'm not very good with electronics, all I know is the power unit was already fitted in the motorhome when we bought it 3 years ago, how would I find out if a 20amp fuse would be safe?
Thanks again for the advice

Remove the fuse and plug 2 spade male connectors in with a 100mm loop of wire between them, then you can clip your clamp meter over it and measure the current

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[scotzsue]

As an aside our fridge fuse also runs some of the habitation lights.

 

[NicM]

Remove the fuse and plug 2 spade male connectors in with a 100mm loop of wire between them, then you can clip your clamp meter over it and measure the current

Yes but he doesn’t know what the current should be does he, there maybe a fault with something.

 

[Dazza 6863]

If you are unsure of sorting it your self then you need to have it looked at by an auto election, as I think you said were.

It's probably something like has been suggested on here ie loose connection or fuse not powerful enough, and I'm not confident enough to start messing with it so ill take your advice and ill ring Sargent tomorrow along with my dealership.
Thanks again for your advice Nic much appreciated

 

[NicM]

It's probably something like has been suggested on here ie loose connection or fuse not powerful enough, and I'm not confident enough to start messing with it so ill take your advice and ill ring Sargent tomorrow along with my dealership.
Thanks again for your advice Nic much appreciated

Yes it probably it something simple, hope it is, good luck with it anyway.

 

[Dazza 6863]

Had the same problem. Spoke with Sargent and according to them Swift have fitted a 15 amp fuse when it should be 20 amp. Following their advice and fitted 20 amp. No further problems at the moment!!
Attached picture of fuse removed and still works

Morning Rico
Update RE Melted fuse,
just got off the phone with Sargent and they have repeated what you said that for the last few years they have changed to using 20 amp
fuses on the over counter fridges which are that larger fridges only and it should have been changed at the Habitation/Service if the dealership got the memo.
Thank you for your advice yesterday much appreciated.
Kind regards Darren