Click here to return to the home page.
Image of a road.
Who's Online Now
23 registered members (ewn, Gordon D, stefan s, Robbie Mathisen, Redfate, TBM, AlyMatt, Ray, JCK, CooperMan, DirkM, NoelD, John V6, peterd, Saxonian, Sinbad, Scrambledsignals, Mick Annick, Leroy, MR11MOG, dogmog, M3W55, Rog G), 243 guests, and 19 spiders.
Key: Admin, Global Mod, Mod
Top Posters(30 Days)
John V6 337
TBM 198
+8Rich 196
Newest Topics
Aero 8 Start issues
by Vianney Colombo. 01/12/20 05:17 PM
New to the forum and Morgan!
by MorGun 3. 01/12/20 04:54 PM
Forum Rules Reminder - Please Read
by TalkMorgan. 01/12/20 04:44 PM
Aerosol Paint can for Sport Ivory Plus4?
by AlyMatt. 01/12/20 04:16 PM
A little Devon speed camera cheque/check ;-)
by +8Rich. 01/12/20 02:53 PM
For Sale - Plus 4 Baby Doll Minilite wheels
by RogerQ. 01/12/20 12:45 PM
2021 NEC Restoration Show New Dates
by mal. 01/12/20 12:29 PM
Latest Photos
FolkMog is celebrating 25th year Anniversary
Best of British IMHO!!!
More November Sun...
November Sun
Is this a 4 to 3 wheeler conversion?
Newest Members
RedSocks, Tim Green, Tyler+8, Karl chapman, Albel
7268 Registered Users
Forum Statistics
Forums34
Topics39,966
Posts662,840
Members7,268
Most Online1,033
Dec 28th, 2019
Today's Birthdays
PSS
Previous Thread
Next Thread
Print Thread
Fuse...not blown.....Just Melted... 2011 Plus 4 #673874
20/11/20 09:45 PM
20/11/20 09:45 PM
Joined: May 2015
Posts: 259
north yorkshire
L
Lowflyer Offline OP
Learner Plates Off!
Lowflyer  Offline OP
Learner Plates Off!
L

Joined: May 2015
Posts: 259
north yorkshire
Wondering if anybody has had the issue. The 8-way fuseboard under the driverside bonnet, first fuse on inboard side of fusebox, 30A. This fuse seems to support everything ! I don't think I've ever used all the consumers at once prior to my run a coup,e of nights ago. However with the fuel pump, heated screen and heater blower running this fuse literally melted (the plastic fuse structure!) due to overload and everything except Hazard lights died. I switched off the non essential loads, blower, heated screen, replaced the fuse and i was away. I need to measure the current with the loads connected so I'll need a 0 to 40 amp ammeter me thinks. I have this wiring loom diagram which i've used before but difficult to interprate into "wiring diagram". Just as an aside the diagram shows a 40A fuse used in one location and checking a similar fuseboard at ECS 30A is max permissable. I think i may need to change the fuseboard due heat damage to the fuse carrier terminals and at the same time separate the circuits via a additional fuses, i.e. install a 10 way board. Has anybody had a similar experiance with this set up.

Re: Fuse...not blown.....Just Melted... 2011 Plus 4 [Re: Lowflyer] #673878
20/11/20 10:11 PM
20/11/20 10:11 PM
Joined: Feb 2016
Posts: 3,230
East Harling, Norfolk UK
Richard Wood Offline
Talk Morgan Addict
Richard Wood  Offline
Talk Morgan Addict

Joined: Feb 2016
Posts: 3,230
East Harling, Norfolk UK
You may be over thinking this issue which might not be overload, especially if the fuse itself didn't blow. The heat generated which melted the holder is likely to be due to a localised resistance in the fuse holder itself, due in turn to dirty contacts. This would cause a volt drop proportional to the total current draw of the circuit and according to Ohms law. The resulting power loss would he dissipated as heat and a significant amount if the current draw was high. I know you said a replacement fuse got you going again but that might be just remaking the dirty contacts so likely only a temporary cure.

Suggest a thorough clean of contacts if the fuse holder is still serviceable. Check also for water ingress which may have corroded contacts.

Last edited by Richard Wood; 20/11/20 10:19 PM.

Richard

2018 Roadster - Red/Magnolia - "Morton"
1966 Land Rover series 2a SWB
1960 Velocette Venom
Re: Fuse...not blown.....Just Melted... 2011 Plus 4 [Re: Lowflyer] #673905
21/11/20 08:25 AM
21/11/20 08:25 AM
Joined: Feb 2016
Posts: 3,230
East Harling, Norfolk UK
Richard Wood Offline
Talk Morgan Addict
Richard Wood  Offline
Talk Morgan Addict

Joined: Feb 2016
Posts: 3,230
East Harling, Norfolk UK
Forgot to add that since power is a product of voltage and current any losses from a given resistance will increase by the square of the current! Indeed in electrical engineering such are often referred to as I2R losses.


Richard

2018 Roadster - Red/Magnolia - "Morton"
1966 Land Rover series 2a SWB
1960 Velocette Venom
Re: Fuse...not blown.....Just Melted... 2011 Plus 4 [Re: Lowflyer] #674000
21/11/20 02:23 PM
21/11/20 02:23 PM
Joined: Jun 2015
Posts: 693
North Somerset, UK
Deejay Offline
Talk Morgan Regular
Deejay  Offline
Talk Morgan Regular

Joined: Jun 2015
Posts: 693
North Somerset, UK
Lowflyer: You may struggle to find a 40A ammeter. Better to connect your ammeter in series with a fuse and then switch on each load individually, record the result and then add them all up to get the total consumption.
Although your car’s equipment stopped functioning, were you saying that the actual fuse element was still intact? Any tell tail arcing or burn marks on the legs of the fuse suggesting poor contact?


Doug

2011 +4 in Rich Maroon
1972 750 “ComDom” sprinter
1958 Triton 650
1992 Triumph Trophy 900
Re: Fuse...not blown.....Just Melted... 2011 Plus 4 [Re: Lowflyer] #674045
21/11/20 07:28 PM
21/11/20 07:28 PM
Joined: Nov 2013
Posts: 411
Huntingdon
S
Scrambledsignals Online content
Learner Plates Off!
Scrambledsignals  Online Content
Learner Plates Off!
S

Joined: Nov 2013
Posts: 411
Huntingdon
I had this issue on my 2013 +4.

Water ingress into the fuse box had helped the contacts to corrode causing the same problem you have.

Re: Fuse...not blown.....Just Melted... 2011 Plus 4 [Re: Lowflyer] #674055
21/11/20 08:44 PM
21/11/20 08:44 PM
Joined: Feb 2016
Posts: 3,230
East Harling, Norfolk UK
Richard Wood Offline
Talk Morgan Addict
Richard Wood  Offline
Talk Morgan Addict

Joined: Feb 2016
Posts: 3,230
East Harling, Norfolk UK
The answer to water induced corrosion would be gold plated fuse holders as offered by some marine electrics suppliers. Chances are limited in getting such a fusebox to match OE though.

BTW I had a similar issue to OP on a yacht. The otherwise well respected builder had secured high current 12 volt connections via eye terminals to stainless M10 bolts through a 15mm plywood mounting board. Although the securing nuts were seemingly tight they offered a marginal connection resistance as the wood simply compressed when I tried further tightening. This was only revealed when I burnt fingers on a very hot bolt. I re-engineered with nuts each side of eye terminals so I could really torque up the connections tight. Adding serrated washers helped. Although such a size bolt would have conducted thousands of amps without issue, it was found the eye connection resistance at each end was enough with the currents flowing, to heat the bolt enough to char the wood over time scared


Richard

2018 Roadster - Red/Magnolia - "Morton"
1966 Land Rover series 2a SWB
1960 Velocette Venom
Re: Fuse...not blown.....Just Melted... 2011 Plus 4 [Re: Lowflyer] #674066
21/11/20 10:17 PM
21/11/20 10:17 PM
Joined: May 2015
Posts: 259
north yorkshire
L
Lowflyer Offline OP
Learner Plates Off!
Lowflyer  Offline OP
Learner Plates Off!
L

Joined: May 2015
Posts: 259
north yorkshire
Thanks for the input gents, I'm sure that there exists some corrison at that particular fuse carrier and i thought I'd got it cleaned up and indeed it had performed ok until as mentioned i switched on all loads, lights, blower, screen, and of course fuel pump.
One of the issues is that Omnitec manufactured "Morgan Dash Control Module", i think its supplied from the same fuse and i think that whilst i was installing an indicator buzzer i accidentally disconnected a wire from it and it also killed everything as i remember....but hey im starting ramble here. That panel i would like a little more info on, its a bit of a mystery and has i believe caused issues for people on here. I did manage to wire my driving lights thro' a spare volt free switch/relay on the panel.
Regarding the suspect fuse csrrier, i think a change out maybe in order which of course means the full 8-way carrier needs to be changed, its a dash drop job. I may choose to just install another carrier and connect the one circuit to it rather than change out all 8 circuits onto a new carrier unless they are spade terminals which would allow for easy changout.
Richard, yes the I^2R heat generated would of course melt the fuse assembly without blowing the fuse, I'd considered this but started to wander of into the hinterlands and vagaries of the Morgan wiring. I guess you've pulled me back on course here. I'd still like to know how much current is pulled via that one fuse.

Re: Fuse...not blown.....Just Melted... 2011 Plus 4 [Re: Lowflyer] #674195
22/11/20 05:35 PM
22/11/20 05:35 PM
Joined: Nov 2015
Posts: 2,985
Yorkshire
CooperMan Online content
Talk Morgan Expert
CooperMan  Online Content
Talk Morgan Expert

Joined: Nov 2015
Posts: 2,985
Yorkshire
Once had some electrical issues on a very large distribution warehouse we built, the electrical contractor used a hand held thermal image camera to test all the dist board connections, let's just say it did show some poor workmanship causing hotspots


Jon M

Moderated by  Aeroman, Simon 

Powered by UBB.threads™ PHP Forum Software 7.7.1