Wiring diagram with ampage requirements?

[MilesA]

Has anyone created a wiring diagram which lists not only cable colours but the appropriate ampage requirements? From time to time, I replace the random bits of cable used when the car was previously restored so that the colours are correct and they are suitable for the load.

Latest job is to replace the two cables going to the overdrive solenoid and switches as these rise vertically from the top of the gearbox cover through a hole in the carpet. I am replacing the carpet and want the cables to be the correct colour and follow a flat route along the tunnel, up the balkhead etc.: easier to identify in future, saves damaging the new carpet and reduces the risk of them being ripped out accidentally. (This is the traditional '1 job in a TR involves two others.!). *

Anyone have a diagram with ampages noted or can confirm what ampage  I need for the cables to solenoid and switches?

Miles

* The other task this has generated is replacing the 3' long onboard speedo cable (L/H drive rev counter cable?) that also rises vertically through the gearbox cover carpet to the speedo!

[RogerH]

Hi Miles,

the OD solenoid takes apprx 17amps but just for a second or so.  Nominally 1amp when actually working

Have a look here at the at the 32/0.2 (16 amp) or 28/0.3 cables (25amp)

http://www.vehicle-wiring-products.eu/section.php/198/1/single-core-pvc-thin-wall-cable

Don't forget the earth return wires that go through the switch these also take the above current.

Look through the above catalogue for connectors etc

Tony C posted a thread the other day where it appears that the solenoid pulled in but did not cut the current and the OD loom got seriously burnt - perhaps a fuse !!

 

Roger

[BlueTR3A-5EKT]

You could go the whole hog and buy the correctly coloured and vinyl taped overdrive gearbox harness pt no 131339. 

Mine exits through a grommet in the LH side of the tunnel, runs forward under the carpet then up to the relay.  It is gaffer taped to the tunnel for security.

The body harness part is pt no 131338, this is in fact a TR4-4A item but works OK on sidescreen cars, but note it has Lucar push on spade connectors for the relay, not screwed terminal types.

Both are in the Moss sale at present.

Cheers

Peter W

https://www.moss-europe.co.uk/catalogsearch/result/?search_group=&q=131338

https://www.moss-europe.co.uk/catalogsearch/result/?search_group=&q=131339

Also from Autosparks  https://www.autosparks.co.uk/finder

Edited July 19, 2019 by BlueTR3A-5EKT

[Tony_C]

Not for me, in my current predicament, to comment on correct or ‘appropriate amperage’; I know mine are not! 

 

However, on much safer ground, happy to share an an old ‘best practice tip from the rally experts from the old days’, run the rev counter cable internally and not outside underneath where it is vulnerable. 

 

Thanks and well done for starting this thread...... (Can’t get enough of overdrive right now)

Edited July 19, 2019 by Tony_C
Format

[John Morrison]

Lots of great stuff here on calculating the correct cable.

https://www.12voltplanet.co.uk/cable-sizing-selection.html

John.

[MilesA]

Chaps

Thanks as ever for your thoughts.

Hadn't thought of the obvious solution of simply buying a pre-prepared harness. Fascinating website John; just need someone who knows how, to apply it to wiring diagrams for our cars. 

John,  take your point about internal routing of the speedo cable. Friend of mine created a rally going MGB and I was fascinated to see all the 'services' routed internally. Bizarrely noticed recently that a friend's Healey 3000 has its loom routed externally which apparently was standard. Think the cable is  reasonably safe on the accepted route for the 3A but if anyone has experience of routing the 84" cable internally, I am listening!

Miles