Goody8

Goody8

New Member
I am in the process of making a loom for my roof mounted spotlights x 5 . My calculation is 5 x 55watts is 275 divided by 12 volts gives roughly 23 Amps. I want to use 25 Amp wire and have seen some 2 core .3 / 25 Amps wire my question is would you expect both cores to be 25 Amp or 25 Amp overall. Either that do I just buy a longer length of single core cable .:confused:
 
12v dc rated I thought . As you say I have also seen thin wall advertised but was dubious of 'thin walled'
 
You want a higher rated cable than 25-30amps.

You may also find it blows 25a fuses as it wont be 23a constant.

I would fuse at 30a and wire 40a.

but maybe some people see that as overkill?

G
 
Goody8 said:
12v dc rated I thought . As you say I have also seen thin wall advertised but was dubious of 'thin walled'
Click to expand...

It's great stuff - for starters it's thin!! My roof lights all have four seperate pairs wires, fuses and relays and the wires run inside the roof bar (and then down inside the snorkle) with ease. Been on for two years without problems. :D
 
Griffdowg said:
You want a higher rated cable than 25-30amps.

You may also find it blows 25a fuses as it wont be 23a constant.

I would fuse at 30a and wire 40a.

but maybe some people see that as overkill?

G
Click to expand...

I won't be 23A either, twould be 275/13V so closer to 21A, id go for a 30A cable, 25A fuse, the fuse is not going to blow as soon as you hit 25A, a quick google gives me a blade fuse of 25A carrying 30A for approx 5 mins before blowing, itll even take 50A for 30 seconds.
 
Cheers everyone for there input I am going to go along the route of thin wall cable, and I am going to run the wires internally in roof rack. For the sake of pence difference I am going to use 40 Amp wire and try running them with a 25Amp fuse. Will check back and let you know how I get on cheers ....
 
Probably will be around 23 not 21 amps as the bulbs are rated for 55watts at 12 volts, with the real potential being 13volts the bulbs will dissipate more power and the same current will flow.

This is the same as mains powered heaters/water heaters where you get different power ratings for 230 and 240 volts but the current flow works out roughly the same.
 
davethsparky said:
Probably will be around 23 not 21 amps as the bulbs are rated for 55watts at 12 volts, with the real potential being 13volts the bulbs will dissipate more power and the same current will flow.

This is the same as mains powered heaters/water heaters where you get different power ratings for 230 and 240 volts but the current flow works out roughly the same.
Click to expand...
:confused: does this mean you think what i am thinking i am going to use is suitable ???...
 
Sorry, didn't mean to confuse you, just trying to explain what will happen with an increase in voltage.

I see no problem with what you are planning to do, 25A sounds right for the fuse and as long as the wire is capable of carrying 25A or more you should be fine as its not travelling far enough for distance to affect it.
 
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