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Fuse Sizes for New Fuse Box

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I've finished all of my modified wiring installing two fuse boxes inside the car, one on-ignition and one on all the time as well as making the changes for the alternator. I've double and triple checked all the circuits and I don't think I will let any smoke out. Now for the final electrical test I have to put in all the fuses for the new fuse boxes. QUESTION IS, WHAT SIZE FUSES? There doesn't appear to be much info about wattage or amperage for the different devices in a Healey. Would anyone happen to have wattage or amperage for the following stuff: Heater Motor, Brake light bulbs, fuel pump, turnsignal bulbs, running like bulbs, Overdrive circuit, Wiper motor, Horns, Instrument gauge bulbs. I did notice that some of my old instrument gauge bulbs may say 2.2 watts. It's very faint. If so that works out to about 0.183 amps per bulb. I'd just round it to about a 1/4 amp. Can anyone help. Thanks, Dave.
 
HI Dave:

Be sure and include a 10 ampere slow blow fuse if you have an overdrive circuit

I did notice that some of my old instrument gauge bulbs may say 2.2 watts. It's very faint.

Yes they are 2.2 Watt items
 
thans for the info fellows. Just for alittle conversation on the subject, I was glad to get the actual sizes from you folks that have done this before. But one point caught my attention immediately and that was the stated 30a fuse for the horns. I known the original fuse that the horns were on was suppose to be a 50a but that fuse also was intended to carry any auxilliary equipment like the radio and cigarette lighter. But seeing that the wires in the harness supplying the horns are no bigger that #14AWG and may really be #16AWG I'm guessing that the horns won't pull anything near 30 amps. But also, the fact that both horns blow at the same time, and they are fed by #14 wire which is rated at 15amps, I will assume that the wire size is marginally oversized for the intended current it is to carry, I think I will try a somewhat smaller fuse for the horns. Have you ever blown the 30amp fuse. I think I will try a 20 amp and see if it holds. Of course if the wire size on the horns is #16, then its ampacity is rated at 7 amps. Seeing that the wire should be oversized for its intended load I believe in that case a 15AMP Fuse should hold. Thanks for the help and I always injoy alittle Sherlock Holmes investigaive analysis. Hope i didn't bore too much. Dave.
 
I forgot I was going to add a pic to show how it came out. I think it will work ok.
 

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vette said:
thans for the info fellows. Just for alittle conversation on the subject, I was glad to get the actual sizes from you folks that have done this before. But one point caught my attention immediately and that was the stated 30a fuse for the horns. I known the original fuse that the horns were on was suppose to be a 50a but that fuse also was intended to carry any auxilliary equipment like the radio and cigarette lighter. But seeing that the wires in the harness supplying the horns are no bigger that #14AWG and may really be #16AWG I'm guessing that the horns won't pull anything near 30 amps. But also, the fact that both horns blow at the same time, and they are fed by #14 wire which is rated at 15amps, I will assume that the wire size is marginally oversized for the intended current it is to carry, I think I will try a somewhat smaller fuse for the horns. Have you ever blown the 30amp fuse. I think I will try a 20 amp and see if it holds. Of course if the wire size on the horns is #16, then its ampacity is rated at 7 amps. Seeing that the wire should be oversized for its intended load I believe in that case a 15AMP Fuse should hold. Thanks for the help and I always injoy alittle Sherlock Holmes investigaive analysis. Hope i didn't bore too much. Dave.
Click to expand...

Naw:
A 15 amp fuse in your horn circuit will be OK. As a matter of fact a 10 Amp slow blow will do you fine..

OTOH; setting fuse size based 0n wire size can get you left on the side of the road :friendly_wink:
 
As usual, Keoke knows his electrics. I don't remember why I used a 30 amp fuse on the horns. Norman Nock has a page in his Tech Talk notes that indicates a properly adjusted horn should draw 2-5 amps (or 4-10 amps for two horns). Because most of us rarely press the horn for long periods of time, a 10 or 15 amp fuse should work fine.
 
GregW said:
As I recall, a US rated 50amp fuse = a 30amp UK rated fuse. At least modern vs. back in the day.
Click to expand...

Good Memory there young fella!!:encouragement:


British Type to American Standard Replacement
50 amp AGC 30
35 amp AGC 25
30 amp AGC 20
25 amp AGC 15
20 amp AGC 10
10 amp AGC 7 1/2
5 amp AGC 3
 
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