I can't seem to find any of these "add a circuit" doohickey's with larger than 16 gauge wire for my mini fuses (unless DWH's source is 14 gauge; the catalog doesn't say). Is 16 gauge with a 15amp fuse adequate/appropriate for the PAC 200A isolator? What's recommended on this thread is 14 gauge/20amp. The isolator draws less than 1 amp when on so in my ignorance, it would seem 16 gauge would be fine, though I would use 14 from the isolator to the "add a fuse" anyway for greater durability.
How to make a cheap isolated dual-battery setup for $50
- Thread starter evldave
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I can't seem to find any of these "add a circuit" doohickey's with larger than 16 gauge wire for my mini fuses (unless DWH's source is 14 gauge; the catalog doesn't say). Is 16 gauge with a 15amp fuse adequate/appropriate for the PAC 200A isolator? What's recommended on this thread is 14 gauge/20amp. The isolator draws less than 1 amp when on so in my ignorance, it would seem 16 gauge would be fine, though I would use 14 from the isolator to the "add a fuse" anyway for greater durability.
patoz
Expedition Leader
The 'Probe' is not grounded. The wire with the alligator clip is the ground, and should be connected to a good clean metal portion of the vehicle that is 'grounded'. Then use the probe to test for a 'hot' contact with the ignition in the 'ON' position.
I don't believe that tester has a battery inside, so without one it is not capable of testing fuse continuity on it's own.
Hillbilly Heaven
Explorer
I have measure the current draw of the PAC or similar type isolators but the data sheets I have for similar contactors shows a coil rating of 12 watts which means about 1 amp. So you should be plenty safe with 16 gauge. I would only use it for 5 amps though.
Here is the data sheet I used for reference. A similar part is 586-902.
https://www.waytekwire.com/datasheet/75580.pdf
Here is the data sheet I used for reference. A similar part is 586-902.
https://www.waytekwire.com/datasheet/75580.pdf
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Hillbilly Heaven
Explorer
Your dohickie thingofamabob it right here. I like this style vs some of the others I have seen. It goes in place of the fuse in your fuse block and the original fuse goes into the thingofamabob. Your add on fuse then has a tap.
ATO/ATC type fuses:
https://www.waytekwire.com/item/46045/ATO-ATC-FUSE-CIRCUIT-TAP/
Mini ATC type fuses:
https://www.waytekwire.com/item/46044/Mini-Fuse-Circuit-Tap-16GA-UL-1015-/
ATO/ATC type fuses:
https://www.waytekwire.com/item/46045/ATO-ATC-FUSE-CIRCUIT-TAP/
Mini ATC type fuses:
https://www.waytekwire.com/item/46044/Mini-Fuse-Circuit-Tap-16GA-UL-1015-/
Hillbilly Heaven
Explorer
That chart is from the NEC and applies mostly to residential and commercial property and AC circuits.
dwh
Tail-End Charlie
It applies to conductor type, insulation type, temperature rating and ampacity. Property has nothing to do with it.
AC. DC. Amps are amps. ("Good. Bad. I'm the guy with the gun.")
Sorry if I wasn't clear. I did ground the tool with the alligator clip and then tested to make sure the bulb worked by touching the probe to the positive battery terminal . Then, with the ground still secured, I probed the fuses.
Hillbilly Heaven
Explorer
You are correct about the NEC chart it will get you in the ballpark but if you follow it to the letter you will strike out. NEC and SAE standards are completely different. Marine charts are about the only decent guy a prosumer can get his hands on. SAE charts you have to be a member and pay for the documents.
There is a reason why the NEC chart fails and that is it does not account for voltage drop, Marine charts do. Lower power circuits 60VDC and less are very sensitive to voltage drop as a percentage. 2% drop at 120 volts AC is a big swing while 2% at 12 Volts DC is a very narrow window. So YES use the Marine charts. Careful with where you source this chart from though. There are so many out there and I have seen many differences in them.
This is a good reference to the problems and it stems from the source.
http://forum.expeditionportal.com/t...amp-ratings-chart-help!?p=1500860#post1500860
Best advice is to follow a known manufacturer's recommendations not a retailer or some internet business. BlueSea has some of the best wiring advice and tech on the internet. Some may say that their numbers are conservative and soft, but it is better than devices failing or worse a fire.
https://www.bluesea.com/resources/1437
DAMN!!! Chrome is blocking advanced editor. Sorry for the large pic I hope everyone can read it.
dwh
Tail-End Charlie
That particular NEC table doesn't take voltage drop into account because voltage drop is irrelevant to ampacity.
Voltage drop determines wire size.
Wire size (ampacity rating) determines fuse size
If the voltage drop requires you to oversize and use say #10, even if the load on that circuit is less than 30a, you still fuse to protect the #10 with a 30a fuse.
There are derating factors which reduce the rated ampacity of a wire, but those are already pretty well covered by the table I posted, which is for wire "inside a conduit or raceway". There's another table for "chassis wiring" (which doesn't mean exactly what it sounds like) that has higher ampacity ratings for a given wire size. Then there is another table for "open air" that has even higher ampacity ratings.
Sticking to the ratings for inside a conduit or raceway is safe and covers just about all the bases.
And since using that table tends to result in oversized wire for a given load, voltage drop is rarely an issue...even if you're dealing with low-voltage DC which, contrary to popular belief, does not use special mystery electrons.
Voltage drop determines wire size.
Wire size (ampacity rating) determines fuse size
If the voltage drop requires you to oversize and use say #10, even if the load on that circuit is less than 30a, you still fuse to protect the #10 with a 30a fuse.
There are derating factors which reduce the rated ampacity of a wire, but those are already pretty well covered by the table I posted, which is for wire "inside a conduit or raceway". There's another table for "chassis wiring" (which doesn't mean exactly what it sounds like) that has higher ampacity ratings for a given wire size. Then there is another table for "open air" that has even higher ampacity ratings.
Sticking to the ratings for inside a conduit or raceway is safe and covers just about all the bases.
And since using that table tends to result in oversized wire for a given load, voltage drop is rarely an issue...even if you're dealing with low-voltage DC which, contrary to popular belief, does not use special mystery electrons.
another_mike
Adventurer
Please.... not the voltage drop again..... ive read this whole thread... not again...
OCD Overland
Explorer
Not mysterious, dwh, magical.
Hillbilly Heaven
Explorer
The average prosumer will find it easier and best if he sticks with Marine tables when doing Automotive wiring. He does not have to go back and do calcs to consider voltage drop and ambient air temps and single conductors in free air.
The Marine table takes all of that into consideration for him. Show me the chart in the NEC that shows voltage vs distance vs amperage. It doesn't exist. Show me in the NEC where it list SAE J1127 and J1128 insulation specs for 105 degree C wire. Trying to make it easier for these guys not throw a bunch of math at them.
The Marine table takes all of that into consideration for him. Show me the chart in the NEC that shows voltage vs distance vs amperage. It doesn't exist. Show me in the NEC where it list SAE J1127 and J1128 insulation specs for 105 degree C wire. Trying to make it easier for these guys not throw a bunch of math at them.
Hillbilly Heaven
Explorer
Just wait I haven't even thrown the Physics into this YET!
dwh
Tail-End Charlie
Magical mystical is only for yellow submarines.