Assessing Amperage

Paint, body preparation and modification, interior work and electrical
loungin112
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Joined: 05 Mar 2014 21:34
Location: Colorado

Assessing Amperage

Postby loungin112 » 21 Jul 2017 19:02

Good evening Realm.

The other day, I removed my fuse box for a vinegar bath. I may need to do another bath, as there is still some grime to be lifted. But, upon inspection, it looks as though I have had at least two fuses fail where fire resulted; melting portions of the fuse box. So, this got me thinking: how can I determine what the correct, and safe, fuse load level is for my vehicle. I could follow what is indicated on the fuse box lid, but who knows whether the fuse box lid is original to the fuse box or is even correct to the vehicle as it is currently configured? I tried a search on this topic - both here and on ratsun - without luck. So, I thought I would pose the inquiry to the experts: "How can you accurately determine the correct fuse amperage to the specific needs of the car?"

Thanks in advance.

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RMS
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Location: Richmond BC Canada

Re: Assessing Amperage

Postby RMS » 21 Jul 2017 20:20

stock harnesses should only be used as a switching feed for relays.
two_68_510s wrote:I guess our donkeys are quicker then your sled dogs!

datzenmike
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Re: Assessing Amperage

Postby datzenmike » 21 Jul 2017 23:07

Dime Quarterly Vol 11 issue 3 has all you need to ID your fuse box. Has the fuse ratings also.

You want enough fuse amperage to supply the needs of what ever is on that line BUT it must not exceed the current carrying ability of the wire on that circuit. The whole point is for the fuse to be the weakest link so that it fails before anything else does.

Fuses heating up and melting the fuse box is solely from resistance between the fuse and he fuse holder or clips. Tarnish or oxidation causes resistance and resistance produces heat. The clips and the fuse must have clean direct contact with no resistance. The problem now is, has the heat removed the spring tension in the clips that hold the fuses. This is a vicious circle as a poor grip can cause a loose fuse with poor contact. The damage is done.
"Nissan 'shit the bed' when they made these, plain and simple." McShagger510 on flattop SUs

loungin112
Posts: 178
Joined: 05 Mar 2014 21:34
Location: Colorado

Re: Assessing Amperage

Postby loungin112 » 23 Jul 2017 20:48

Thanks everyone. Seems as though my fuse box is an odd-ball from what is noted in the DQ. Four...4!!! wires exiting from under the fuse box. Why is it that wiring usually takes the most punishment from previous owners of 510s? I'm hoping one of the extra leads is from factory installed A/C. I'm going to put a voltmeter to the fuse box before driving any distance that is too far.

datzenmike
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Joined: 24 May 2006 12:40
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Re: Assessing Amperage

Postby datzenmike » 24 Jul 2017 07:09

If you replace with another box.. remove the fuses, clean thoroughly and soak over night in a solution of lemon juice and salt. In the morning, clean thoroughly and air dry. This will remove only the copper/brass tarnish and provide a good electrical contact with the new fuses.
"Nissan 'shit the bed' when they made these, plain and simple." McShagger510 on flattop SUs


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