Cable size for my new (to me anyway) eberspacher D2L

[ChrisKaye]

Sorry to bore people on here with more eber stuff, just a quickie I promise. Just getting all my stuff ready for to do the installation over the coming week.
Is this cable I've just bought going to be big enough from battery to eberspacher loom:- Twin core 28/.30. Supposedly Ok for up to 28 Amps ??

 

[andyball]

Hi Chris

that all depends how long the cable run is... I would try to keep the volt-drop ( based on starting current ) as small as poss, say under 0.5Volts.


VOLT DROP FORMULA


E =


<u>0.0164 x I x L</u>
S
where:

E = Volt drop in volts
S = The conductor cross sectional area in sq. mm.
I = The load current in amperes
L = The total length in metres of the conductor from the positive power connection to the electrical device and back to the negative source connection.

 

[ChrisKaye]

Hi Andy
Cable run is going to be no more than 5 metres.
E=010164 x 20 x 5 (think I got that bit !) but the cable only says 28/.30 28 is the amps its OK for or so the bloke in the shop told me, so does that mean its 3mm cross sectional area ?

 

[andyball]

28/30 is 2 sq mm cable - soo if a total run there & back of 5metres.... you'll lose around 0.8V when the glow plug is operating ( assuming the plug & fan together draw 20Amps). Less a bit for the fuse & holder too.

I would go larger myself, but it'll certainly work ok when new & with charged batteries .

 

[ShipsWoofy]

This works!

 

[ChrisKaye]

Thanks everyone.
So as long as I dont go much longer than 3 metres (.492) , i should be OK with the 2mm cable that I have right ?
Any longer and its going to have to be a trip into local leccy store for thicker cable

 

[ShipsWoofy]

[ QUOTE ]
Thanks everyone.
So as long as I dont go much longer than 3 metres (.492) , i should be OK with the 2mm cable that I have right ?
Any longer and its going to have to be a trip into local leccy store for thicker cable

[/ QUOTE ]

Ok, that's the maths, but I would not dream of using 2mm bell-wire on an eber, the start-up current can be up to 25A, you may find the cable aids the warming process somewhat.

 

[ChrisKaye]

Whoa !
Better get thicker cable then
Thanks Dogwatch

 

[pappaecho]

If the only real load is a glow plug operating for a few seconds, you should be OK assuming that your cable run is not enclosed, so if it gets warm for a few seconds, it can dissipate the heat. Mine is fused 8 amps and has run for years on the standard issue cable

 

[ShipsWoofy]

Sorry, not meant to scare monger, too much, but experience showed me that using the lighter cable just does not cut it. You may get away with lighter cable if you always start the engine prior to the eber, but that is impractical and 0.8v drop during start up is being very very conservative IMO, even with brand new batteries.

I just would not entertain cable as suggested, even though on paper it is ok (in perfect conditions).

Do remember to fit a fuse in the power cable too, I have an in-line Strip/midi fuse holder like this one, glass or blade just wont be up to it -

I have a 40A Midi fuse fitted

Try http://www.vehicle-wiring-products.co.uk for any components you might need.

 

[misterg]

[ QUOTE ]
cable only says 28/.30 28 is the amps its OK for or so the bloke in the shop told me, so does that mean its 3mm cross sectional area ?

[/ QUOTE ]

28/0.30 means 28 strands, each 0.3mm in diameter, which works out at 2mm^2 cross sectional area.

Note that the volt drop calculation requires the 'round trip' distance of the cable run - i.e. usually twice the distance from the switchboard to the doofer - sorry if you've already spotted this - grandmother, eggs, etc.

Given the number of posts that pop up here (September / October time, usually) about eber problems stemming from low voltage, I'd make absolutely sure I had 'generously' rated cables to supply it.

0.02p

Andy

 

[andyball]

at four quid a metre, I assume it makes the tea too?

 

[ChrisKaye]

Thanks everyone, will report back if succesfull. If not succesfull I am sure you will hear on news !
Regards Chris

 

[ChrisKaye]

Thanks everyone for help on here and esp Skipper Stu who supplied the unit.

I now have an eber and it works perfectly !!!