2 wire versus 3 wire circuit breaker?

[busmania]

I ordered the nos 33-40 circuit breaker from third gen. It arrived today. It has 3 studs for wires, my old one only had 2 studs. The wiring diagram also only shows two studs. Is my new 3 wire one usable?

Working on a 40. Was this a transition year maybe?

The 3 wire is labeled “B” “H” and “A”. I’m assuming B for battery but what did A and H stand for?

Is there a way to test the old one? Maybe I’ll just use it.

Photos.

E110ED0F-2E92-464A-AFD3-DD09E505C0DC.jpg

B88759DD-D46D-4FB6-84E7-38384C2131C6.jpg

[1942deluxe]

The H stands for headlamps and the A stands for AMP and B is battery to my knowledge. On my 42 all the other lights on the car were connected to the A circuit. 40 may be entirely different. The smaller one looks like the correct one to me where the other one looks like the 41 up style. Hopefully Kube will chime in...

[Kube]

Originally Posted by busmania

I ordered the nos 33-40 circuit breaker from third gen. It arrived today. It has 3 studs for wires, my old one only had 2 studs. The wiring diagram also only shows two studs. Is my new 3 wire one usable?

Working on a 40. Was this a transition year maybe?

The 3 wire is labeled “B” “H” and “A”. I’m assuming B for battery but what did A and H stand for?

Is there a way to test the old one? Maybe I’ll just use it.

Photos.

Attachment 536204

Attachment 536205

You may be able to use that, but it most certainly is not correct for your '40.
Personally, I'd find the correct part.

[busmania]

Thank you. Is there a way to test my original? I was really hopi g to have the wiring done tomorrow. Oh well! That’s how it goes usually.

And, on the original how do I know which side is battery? The original is not labeled.

Or is bypassing it and just installing a fuse there an option? I suck at electrical!

[JayChicago]

Originally Posted by busmania

Thank you. Is there a way to test my original? I was really hopi g to have the wiring done tomorrow. Oh well! That’s how it goes usually.

And, on the original how do I know which side is battery? The original is not labeled.

Or is bypassing it and just installing a fuse there an option? I suck at electrical!

I would reinstall the original. Chances are it will work fine, both the circuit breaker and the ignition resistor.

Probably does not matter which way the circuit breaker is wired. The circuit breaker probably is just a bi-metal strip that will open when it gets too hot from carrying too much current. Which way the current is going probably does not matter.
The resistor definitely does not care which way it is wired.

Those cylindrical things in the pic are condensers for radio static suppression. You don’t need those. Old condensers are almost always defective anyway.

[busmania]

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That helps thank you.

I’m nervous when I plug my battery in everything’s gonna go boom and my $1500 in wiring gonna be toast!

[Terry,OH]

You can check it by placing an ohmmeter across the two terminals, it should be nearly Zero ohms if good. It is possible to pry one side of the cage open and clean the contacts and reclose the pried up side when done. Do follow the 40 wiring diagram color code so that you get all the wires on in the proper order. Mac Vanpelt web site has the diagrams from Ford.

[busmania]

Thanks. My wiring is a little different from stock as Rhode Island wiring makes it to your specs (turn signals added, 2nd tail light etc) but it’s basically the same layout and using Rhode Island’s diagrams and the original diagrams, I am close. Can anyone confirm if the side I put the wires on matter? I should be working on it this afterNoon.

[pistonbroke]

As stated earlier if using the two wire it doesn't mater. if using the three , B=battery or power supply, H= headlights and A= amp gauge. The ballast resistor can go either way if your coil even needs one. I'm solid on this having done many over the years. If your worried, put a 20 amp inline fuse from the parts store between the battery and the lug on your solenoid where your battery cable goes. It will not run your starter and probably not your head lights but all your gauges tail an turn and dash lights should work. if it pops then you have a short. One last thing leave the coil disconnected as this to could cause the fuse to pop. Tim

[Jack E/NJ]

> > Is there a way to test my original?> >I’m nervous when I plug my battery in everything’s gonna go boom and my $1500 in wiring gonna be toast!>>


A good automotive breaker should reliably cut power if a live wire is shorted. Operative word is 'should' as opposed to 'will'. Because if it doesn't, your '$1500 in wiring gonna be toast' and a fire hazard. This is partly why I still prefer fuses or fusible links in my car.

[busmania]

I’m open to a fuse. Is it as Simple as wiring a20 amp (or 30 or whatever) in place of the breaker box? Again, electrical not my strong suit!

[pistonbroke]

Which cost more, your 40 ford or your house ? We have to have circuit breakers in our home to meet code . fusses are on their way out. This is one point ole Henry was way ahead of his time. Tim

[Jack E/NJ]

Nope. Breakers have mechanical parts subject to shock, vibration, dust, water, oil, etc Henry's breakers were more like old style bi-metallic strip furnace thermostats that weren't particularly reliable.



Unless using more expensive marine or aviation-grade breakers, fuses are considered more reliable in cars & trucks. Even outside HVAC service disconnects often use --- and codes require --- fuses.

[rotorwrench]

Short Stop type breakers were used for decades and especially on trucks for all the lighting they have. When they fail, it is generally in the open position. If they are working, they will immediately open the circuit and then set that way till they cool down enough to reset. It would continue to open again until the short circuit is corrected.

Do a test off the car using spare wiring or jumpers and the appropriate battery. To open the breaker just short the power output side direct to ground. It should click open rather quickly due to the extreme heat generated by a dead short to ground. If it doesn't open then it is bad and your only out a short section of wire. Caution: don't hold the wire that is grounded with your fingers or they could get burned. Use a pair of pliers or what have you.

[petehoovie]