Author Topic: Wire size help  (Read 503 times)

Offline RoyC

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Wire size help
« on: 22.08. 2017 12:45 »
I am getting ready to wire in my front brake cable stop switch.
There are two LED stop lights drawing a total of 8w (4w each).
I have 11A cable .5mm. Is this big enough to carry the load ?
Thanks,
Roy.
My bike is a 1958 A7SS
Staffordshire UK

Online KiwiGF

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Re: Wire size help
« Reply #1 on: 22.08. 2017 12:53 »
I am getting ready to wire in my front brake cable stop switch.
There are two LED stop lights drawing a total of 8w (4w each).
I have 11A cable .5mm. Is this big enough to carry the load ?
Thanks,
Roy.

Yes, in case it helps, volts x amps = watts, or alternatively watts/volts=amps, so 8 watts/12 volts= 0.66amps. The smallest of wires will carry that!



Simple,eh?
New Zealand

1956 A10 Golden Flash (1st finished project)

1949 B31 rigid “400cc hot rod” (2nd finished project, + favourite bike)

GL1800 Goldwing, well, the wife likes it

KTM 950 ADV, cos it’s 100% nuts

1952 Armstrong Siddeley Whitley for rainy days (with wife)

Offline RoyC

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Re: Wire size help
« Reply #2 on: 22.08. 2017 13:01 »
I am getting ready to wire in my front brake cable stop switch.
There are two LED stop lights drawing a total of 8w (4w each).
I have 11A cable .5mm. Is this big enough to carry the load ?
Thanks,
Roy.

Yes, in case it helps, volts x amps = watts, or alternatively watts/volts=amps, so 8 watts/12 volts= 0.66amps. The smallest of wires will carry that!



Simple,eh?

Thanks a lot for that confirmation and the formula.
Roy.
My bike is a 1958 A7SS
Staffordshire UK

Online mikeb

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Re: Wire size help
« Reply #3 on: 23.08. 2017 01:00 »
agree - you are good to go. fyi the current carrying of different wire gauges and number of strands is easy to find online. eg here: http://www.engineeringtoolbox.com/wire-gauges-d_419.html. that suggests at 0.5mm copper dia = 24g = you've got at least 1 amp and probably more depending on how many strands.
another consideration is the other physical properties of the cable, especially if subject to movement and weather. more strands is more flexible but for lower amperage (than fewer strands). some cheap wire has soft plastic outer and not good in the weather. always go a bit fatter than you need. copper wires are durable and easy to solder but corrode eventually especially at the ends. other metals like ?aluminium? can turn up in cables but are hard to join except by crimping (won't solder) . i get a bit ocd on this stuff and always use copper wires and solderable crimp connectors - ie solder the back once crimped. just crimping risks the wire dislodging / high resistance. do it right so you don't have to worry about having intermittent electrical faults.
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'61 Super Rocket  - '47 B33 -  '18 Triumph Street Triple RS

Offline RoyC

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Re: Wire size help
« Reply #4 on: 23.08. 2017 14:13 »
Thanks for that Mike.
Roy. *thanks*
My bike is a 1958 A7SS
Staffordshire UK

Offline coater87

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Re: Wire size help
« Reply #5 on: 23.08. 2017 22:30 »
 Im having flash backs to my electrical apprenticeship days.

 Memorizing formulas for things like inductive capacitance.

 Thats time I will never get back, and I have never once used that formula for anything....  *rant*

 Ohms law on the other hand is a must have.

 Lee
Central Wisconsin in the U.S.

Online BSA_54A10

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Re: Wire size help
« Reply #6 on: 24.08. 2017 11:11 »
Boating shops keep the original tin plated copper wire in most original Lucas colours if you are interested.
marine wire will be better all over than auto wire.
However quality is not cheap.
Bike Beesa
Trevor

Online Greybeard

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Re: Wire size help
« Reply #7 on: 24.08. 2017 18:00 »
Im having flash backs to my electrical apprenticeship days.

 Memorizing formulas for things like inductive capacitance.

 Thats time I will never get back, and I have never once used that formula for anything....  *rant*

 Ohms law on the other hand is a must have.

 Lee

You are so right about learning stuff that you have never used and will never use: "One over two Pi Route LC, is the resonant frequency" or 1/2PI*SQRT(LC)
https://www.eevblog.com/forum/projects/resonant-lc-circuits/

Offline coater87

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Re: Wire size help
« Reply #8 on: 27.08. 2017 02:09 »
 I followed your link.

 I could suddenly smell my instructors over powering cologne and the cheap cigar smell he was trying to cover up with it. *sad2*

 It's why I like the old bikes so much.

 They never smell like dork.
Central Wisconsin in the U.S.