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alexatnd



Member Since: 19 May 2015
Location: Yorkshire
Posts: 111

United Kingdom 
Rating of cable to +ve battery terminal

I'm looking to connect one of these https://www.mudstuff.co.uk/blue-sea-fuse-block.html to the +ve battery terminal on my TD5 110. However this necessitates the replacement of the existing +ve feed with a different shaped clamp as the one thats there has the cable feeding directly into the clamp and its not removable.

Thought I'd just replace the whole existing cable with on with appropriate battery terminal eyes at each end. Found some for 16mm^2 cable and stud sizes.

know the stud size hole will depend on the clamp I'm using, but does 16mm^2 cable sound the right size ? Santa - 1977 Series 3
Gertie - 1999 110 TD5 - like a Phoenix from the ashes back on road
Effie - 2004 110 TD5 County

Post #717170 11th Jul 2018 2:35pm
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nitram17



Member Since: 08 Jun 2014
Location: newcastle
Posts: 1235

Poor response to your question fella!i think this place is getting less helpful over the past year!.......if i was doing the job i would go for 35mm2 cable or greater .........in this case thicker is better Laughing ..........provided the cable is flexible enough to fit..........perhaps a sparky may want to comment?

Post #724721 21st Aug 2018 10:19pm
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miker



Member Since: 13 Sep 2015
Location: West London
Posts: 1328

United Kingdom 1999 Defender 110 Td5 CSW Rioja Red

Pretty certain the original is 25mm. Runs to the fusebox under driver seat and the starter motor, but I can't remember where the split is!

To be honest, I wouldn't bother. I've got a ring crimp under the nut and bolt on the terminal clamp. Works great, no need to rip out the existing cabling.

Post #724726 21st Aug 2018 10:38pm
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custom90steve



Member Since: 21 Jan 2010
Location: South West England
Posts: 16381

United Kingdom 2007 Defender 90 Puma 2.4 SW Stornoway Grey

It will need to be rated higher than the output of the Alternator.

Different sizes have different current ratings, but the cable current rating will need to exceed the Alternator output.

ALM Electrical do a good selection of 'flexible' plain battery cables. I have no connection with them but have been very good.
Don't go for any old battery or welding cable, some can be extremely stiff and make it near impossible to install and route neatly.
Alternatively check out OFC or TOFC car audio cable, this should be very flexible too and I'd imagine you'd want something like 4ga but you cannot guesstimate in this instance.

Do you have a photo of your battery post set up? Watts ÷ Volts = Amps.
Amps X Volts = Watts

Post #724732 21st Aug 2018 11:15pm
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PaulMc



Member Since: 17 Jan 2009
Location: Kent
Posts: 349

United Kingdom 1989 Defender 110 2.5 TD HT Arles Blue

According to Land Rover's Electrical Wiring Diagrams for the 2002MY TD5 Defender -

The live from the battery to the starter is 40mm²

The battery earth is 40mm²

The live from the battery to the underseat fuse box is 10mm²

. Paul.
1989 Arles Blue 2.5TD 110 Hardtop
1999 Epsom Green Discovery II 4.0 V8i 'XS'

Post #724737 22nd Aug 2018 1:05am
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Marks Landy



Member Since: 09 Feb 2015
Location: Cheshire
Posts: 95

United Kingdom 1985 Defender 90 200 Tdi SW Java Black

The positive battery cable on my 200TDI is 25mm2.

Post #724759 22nd Aug 2018 8:57am
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nitram17



Member Since: 08 Jun 2014
Location: newcastle
Posts: 1235

I don't know about the OP.......but I am now confused!do people go for the minimum thickness they can get away with or the maximum they can use with regard to flexibility..".i thought that 35mm2 cable was about right for jump leads so by inference.......must be ok for battery leads on the defender!

Post #724797 22nd Aug 2018 12:45pm
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nitram17



Member Since: 08 Jun 2014
Location: newcastle
Posts: 1235

PaulMc wrote:
According to Land Rover's Electrical Wiring Diagrams for the 2002MY TD5 Defender -

The live from the battery to the starter is 40mm²

The battery earth is 40mm²

The live from the battery to the underseat fuse box is 10mm²

.


Having looked at the legend on the wiring diagram it states 40mm OD but is that including the insulation?whats the convention for wire rating?

Post #724801 22nd Aug 2018 1:00pm
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PaulMc



Member Since: 17 Jan 2009
Location: Kent
Posts: 349

United Kingdom 1989 Defender 110 2.5 TD HT Arles Blue

It's shown as - 40.0

From the HOW TO USE THE CIRCUIT DIAGRAMS at the front of the wiring diagrams -

Wire attributes
Additional information (separated by a ‘,’) is shown alongside the wire colour:
Wire gauge - the cross-sectional area of the wire in square millimetres.
This is included to help you select the correct wire during harness repair. Paul.
1989 Arles Blue 2.5TD 110 Hardtop
1999 Epsom Green Discovery II 4.0 V8i 'XS'

Post #724837 22nd Aug 2018 2:51pm
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blackwolf



Member Since: 03 Nov 2009
Location: South West England
Posts: 8845

United Kingdom 2007 Defender 110 Puma 2.4 DCPU Stornoway Grey

nitram17 wrote:
... Having looked at the legend on the wiring diagram it states 40mm OD but is that including the insulation?whats the convention for wire rating?


An electrical conductor with an OD of 40mm would have a CSA in excess of 1200mm^2 and would be a little OTT for this application! Shocked

Post #724849 22nd Aug 2018 3:33pm
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nitram17



Member Since: 08 Jun 2014
Location: newcastle
Posts: 1235

PaulMc wrote:
It's shown as - 40.0

From the HOW TO USE THE CIRCUIT DIAGRAMS at the front of the wiring diagrams -

Wire attributes
Additional information (separated by a ‘,’) is shown alongside the wire colour:
Wire gauge - the cross-sectional area of the wire in square millimetres.
This is included to help you select the correct wire during harness repair.


Thanks .so the 40mmo d refers to the metal wire and does not include the insulation........40mm is some thick wire then!

cross sectional area is not the same as diameter though?..i think i will visit confused dot com Rolling with laughter doesnt 35mm2 wire have a diameter of 11.9 mmish?wheres a sparky when you want one?

Post #724953 22nd Aug 2018 9:29pm
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steve_c3



Member Since: 30 Apr 2015
Location: Hants
Posts: 115

United Kingdom 2002 Defender 110 Td5 SW Epsom Green

I’m not a sparky but is it as simple as working out the area of a circle from it’s radius? The website below makes it easy...just put the area as 40mm2 or whatever and it will tell you the Diameter of the circle or in this case the width of the wire.

From an electrical point of view though, I don’t know whether the mm2 measurement includes the insulation or not.

https://www.calculator.net/circle-calculat...0&y=25 2002 Defender 110 CSW TD5

Post #724965 22nd Aug 2018 10:45pm
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nitram17



Member Since: 08 Jun 2014
Location: newcastle
Posts: 1235

nitram17 wrote:
PaulMc wrote:
According to Land Rover's Electrical Wiring Diagrams for the 2002MY TD5 Defender -

The live from the battery to the starter is 40mm²

The battery earth is 40mm²

The live from the battery to the underseat fuse box is 10mm²

.


Having looked at the legend on the wiring diagram it states 40mm OD but is that including the insulation?whats the convention for wire rating?


i need a brain dat scan and a new pair of specs Embarassed i mis read the diagram!

Post #724970 22nd Aug 2018 11:02pm
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apt100



Member Since: 05 Mar 2015
Location: Derbyshire
Posts: 1460

United Kingdom 2016 Defender 90 Puma 2.2 XS CSW Aintree Green

^^ the cross sectional area (eg 40mm2 or 35mm2 or whatever) is the area of the copper as this is what carries the current. It doesn't include the insulation Thumbs Up

and as you say it is just the area of a circle, so area= pi x radius x radius (and radius is half the diameter)

so, as above... 40mm diameter is 20mm radius, so area = pi x 20 x 20 = 3andabit x 400 = 1200mm2 andabit

edit: my reply was to steve


Last edited by apt100 on 22nd Aug 2018 11:10pm. Edited 1 time in total

Post #724971 22nd Aug 2018 11:09pm
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nitram17



Member Since: 08 Jun 2014
Location: newcastle
Posts: 1235

blackwolf wrote:
nitram17 wrote:
... Having looked at the legend on the wiring diagram it states 40mm OD but is that including the insulation?whats the convention for wire rating?


An electrical conductor with an OD of 40mm would have a CSA in excess of 1200mm^2 and would be a little OTT for this application! Shocked

Right as always blackwolf!... this gives both od and mm2 http://www.vehicle-wiring-products.eu/prod...e........I misread zero d on the electrical diagram and took it for. OD outside diameter because I'm getting old and befuddled.....anyway a minimum of 25mm2 would be my choice for battery cable but when joining cable I would always use like for like ...therefore 40 mm2 on the 2002 would be my choice .

Post #724972 22nd Aug 2018 11:09pm
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