15 AMPS or MORE... Solder all connections!

Black-Tooth

Black-Tooth

Tony Natoli
Also... what I learned today about Factory Crimps.

The foto below is of TWO 25 amp rated fuse holders with 30 amp fuses that came in them... ganged together. They had pigtails with which I soldered terminal ends to and screwed them down onto a terminal strip... to operate two 25 amp radiator fans in my Vette.

When initialized, the fans spike to about 25 amps and then settle in at about 7 apiece.



Both fans eventually failed to operate last Friday on a 17 mile trip home with A/C on. The wiring burned OPEN just where they were crimped onto the terminals inside the cases where the fuses are located... and all this came from the factory like this.



I had to cut the remainder of the wiring off... and then tested the fuses... as it sat, as the cases were melted shut. Both fuses never blew! Some protection huh!

I tested everything and rewired the system without fuses and everything worked flawlessly. I plan on getting a 50 amp breaker for the entire system and then wire in two 30 amp breakers for each fan as well.

So... here I am still learning through experiences... most of which are bad. I guess unless you go to McMaster-Carr (or a similar supplier) its difficult to find decent terminals and electrical parts.

I don't think I'm gonna try and crimp ANYTHING ever again...
 
25 amp fuses need 25 amp wire

Which might be part of the problem.
Over-fusing a wire (by the looks of what you have) is likely the issue.

25 amps require wire that's LARGER than 12Ga. 10Ga is preferred.
I know of at least 1 Italian auto maker that ignores that. :grin:

You can't melt a fuse holder like that with only 7 amps unless there's a LOT of resistance at the junction.
Soldering helps a lot, but if the wire can't take it, you still have an issue.

Sorry to hear of your troubles.
 
It's unclear from your post whether you are saying the failure was crimped or crimped and soldered. I ask because in many circles, soldering a crimp connection can create a rigid connection where flexibility is needed, and the wire will break next to the solder if the wire is not made rigid somehow. This can cause overheating as you experienced, in addition to what Bob mentions.

Fuses don't necessarily protect against overloading, they protect against shorts, not the same kind of protection.

Some automakers solder their connections as well as crimp them. BMW for instance; on Dr. Wifey's 320i the tail light wire connections are soldered as well as crimped, but the solder point is at the very end of the wire, on the opposite side of the crimp from the rest of the wire. If solder wicks into the crimp or up the wire past the crimp, it can cause fatigue.
 
Bob, Greg... thanks for your response...

Yes, the wiring was 10 gauge and the wiring and factory crimps to the terminals INSIDE the fuse holder were untouched by me.

I took the factory pig-tails and soldered round tipped terminal ends to them and screwed then down to a terminal strip. The output of the terminal strip went to each + lead of a fan, in this case. The terminal strip issa nicea place to connect everything together and also to easily swap the LEAD fan every so often, to even out the usage.

If you can read the printing on the burned up sticker (I moved so that it could be photographed...) It reads a MAXIMUM CONTINUOUS 25 amp rating... came with 30 amp fuses... and came with the fans originally!

When I used a "clip-on" ammeter and tested I saw an instantaneous spike as described and then the draw was very low once running. I may have just encountered a couple of defective units... but there was no evidence of over heating anywhere else leading into or out of these fuses.

Hopefully I'll not haveta add more to this post... and its over with...
 
NAPA stores seem to carry good quality wiring products. The other major parts chains seem to all have the same stuff, IMO not as good for the same price as NAPA.

Regarding the wire itself, I have seen inexpensive "eBay" wiring that, even though it carried the same AWG gauge number, and on the exterior the diameter of the wire was comparable to same-AWG NAPA wire, the actual diameter of the copper wire bundle inside the insulation was significantly smaller than the NAPA product.
 
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Thanks for the tip, Dan. I have a NAPA store nearby...

but not the most convenient.

But if the stuff is as you say... then a trip to them will be a lot less hassle than doing things over and over again!
 
Sounds like the fuse holder was not rated for the amperage of the circuit or the fuse then.

Sort of like how it's pretty common to put 15A outlets on a 20A circuit in a house. It will work, but if you overload the circuit, the outlet may fail before the breaker trips. This is how fires are started. Why would anyone do this? 15A outlets are $2.50 cheaper than 20A outlets.
 
I didn't know you could still find 15A outlets...

If new construction, the builder probably had a bunch of these in boxes laying around and decided to rid himself of them.

As for my problem... it was the Brand Name Fan and Controller manufacturer that provided these. I agree as well, the fuse holders were definitely not suited for the 25 amp CONTINUOUS task... even though the draw was much less.
 
(off topic)

In houses in the USA, 15A outlets are common and code approved for 15A circuits using 14g wire. 20A outlets have that funny t-shaped neutral slot. The problem arises when someone puts a 15A outlet on a 20A circuit using 12g wire. The outlets have small holes on the back that 12g wire won't fit into. But, you can use the screws on the sides to "side-wire" them. This is the better, if slower, method anyway.

Outlets.JPG
 
Those connectors look awful small for their 25 amp circuits. It is very typical of consumer/budget manufactures to push everything to the very limits and a bit more for cost reduction and more profit. "Factory" does not mean technically correct or properly engineered, it simply means the item has been mass produced in a "Factory".

For OEM product manufactures with legal product liability, they generally will engineer with a bit more design margin to reduce the possibility of being sued for product failures like this. For aftermarket stuff, most anything goes as much of this stuff is sold with a legal disclaimer as one of the legal devices to protect themselves.

Here is a link to one spade connection manufacture and their product recommendations for how they should be used.
http://www.te.com/catalog/menu/en/17703?BML=10576,17560,17698

What size are the connections that failed? It very possible the failure was due to a defective crimp or the connector is being used beyond it's rating.

Crimp terminals are reliable only if they are applied properly as there are many millions upon millions of these connections in service world wide. Like most things that are not properly applied, failure will happen.

Suggestion would be to rid the fan circuit of this stuff and install parts that are rated for no less than 25A continuous service current, not peak. This includes wire size, connectors and all related parts. Crimps are fine only if matching tooling and connectors are used, properly done solder joints are fine if attention is paid to their mechanical requirements.

Any connection improperly made will result in problems.


Bernice
 
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