MTFCA Forum

I want to put an inline fuse in my 23 . It would be a fuse holder and what amperage fuse should I use?

Suggested is a 20 amp fuse with the holder soldered inline on the yellow battery #12 gauge wire at the foot starter switch terminal .... not on the starter cable terminal.

John. I installed mine right at the firewall terminal block. used a black in line fuse holder with 20 amp fuse. Might use a black fuse holder so it not too obvious. Many put their fuse holder at the starter switch in a weather proof boot like some of the vendors sell. I prefer to mount it on fire wall where it is easily to change fuse or disable electrical power when working on the car. Sure from a purely technical point of view fuse at the power source. But in this case the 30 inches ? of wire run straight to the fuse holder stands little chance of shorting out on anything. and it is much easier to check or change when out on the road in the boonies with out getting under the car or pulling the floor boards in the dark. Photo of period after market model T fuse block that fuses all of the model T electrical circuits including the magneto. A little over kill. Maybe not when You compare against Your daily driver with fifty fuses and three or more fuse boxes. Henry didn't put fuses on the model T because they were not needed but they cost a Nickle. He did put fuses on the model A to keep up with the competition such as Chevrolet and others which had put fuses on their cars for years.

Robert & John are spot on but 3 years from now when the car wont start & you forgot you installed a fuse that cant be seen it will drive you nuts.
Just a personal observation. Not admitting to anything your Honor.
Craig.

Craig and All ..... No harm taken,.... Another fuse location could be tapped right off the battery terminal itself, with an additional wire ran to meet the original harness at the starter switch area. Here again, location location, location, location, location... Touring car would be no problem, Depot hack, here again no problem, going for a roadster Is another story having to move things around in the trunk just to get to the battery .. or trying to get access in spite of a larger gut, here again, no harm taken. So we do have an option of three locations for a safe fuse addition..... Running an extra length of wire with a fuse at the positive battery terminal, an additional fuse at the firewall terminal block, or adding the fuse at the battery terminal of the starter foot switch. Some of us do not want to have others see the changes that we incorporate.... It's all a matter of personal preference and safety....... The the addition of a master battery switch mounted on the front seat riser Is a thoughtful safety feature with the standard wiring.

John
The Model T Ford FA charging and lighting system is a 20 amp system that should be fused with one 25 amp fuse.
That fuse should be installed as shown in the attached wiring diagram. This fuse will protect all the cirsuits form overload.
Ron Patterson

"Fuse should be installed as shown". ..... ????? I have my glasses on but I can't find the fuse. Please highlight that area.

Read the note in the lower right side of the print.

Jeff... I did read the notation, .... highlighting the diagram area would be more helpful to more.

For the brake and turn signals I added an additional 15 amp fuse at the starter switch to power those items. It will make the ammeter show a charge when activated, but to me is the best point for protecting the circuit.

Moxie26 wrote: ↑

Sat Jun 15, 2024 9:59 am

Jeff... I did read the notation, .... highlighting the diagram area would be more helpful to more.

Did that awhile ago for a different discussion. Note UPPER case vs lower case letters --
--
Same basic diagram with color coded wires

Fuse options
Circuit Breaker --
conventional --
Just hang it from the terminal strip

I understand where to put the fuse, but why should it be as close to G as possible? Why not anywhere between G and 3?

The further into the wiring system the fuse is placed, there is a greater the chance of damage between the power source and the fuse. So, keep it at the starter switch, out of sight. It is not as accessible, but you have to find the reason the fuse blew in the first place, so adding replacing the floorboards to the task is no big deal.

Allan from down under

"Why should it be as close to G as possible?" Closer to the Battery source the more protection.

G is the battery source.

Easier to access from under the car rather than through the floorboards.