Has anyone changed their electrical distribution?

[Healey_Z]

This is my first British car that I have owned. I just can't see how system that has only two circuits, one with a 35A fuse, and one with a 50A fuse is the best design.

 

[RAC68]

Hi Healey Z,

To answer your first question, YES, many of us have added fuses and/or split circuits for better protection with some also adding upgraded harnesses.

As for the fuses mentioned, British fuses are designed differently and 35 Amp and 50 Amp Lucas fuses translate to 17 Amp and 35 Amp US. With the 35 Amp US fuse only supporting the horn, all other protected devices (Brake Switch/Fuel Gauge/Rev Counter/Wiper Motor/Flasher/Heater Switch-Blower) are protected by the one remaining 17 Amp fuse. As you have already concluded, a number of key electrical components are left unprotected and vulnerable.

Keep in mind that when the Healey was designed and manufactured, thin wiring gauge was up to supporting the low draw of all electrical components provided and the very few options commonly available. Today, additional electrical demand is being placed on these circuits by much higher powered head and driving lights, added radiator fans, more sophisticated sound systems and even air conditioning and cruse control. To address this updated demand, many of us have either separated and upgraded the wiring supporting these devices or, at the very least, incorporated additional fusing.

For my part, I have chosen to incorporate added in-line fuses on all critical and optional circuits (approximately 13 additional) and now have separate protection through a cabin power master and individual headlight, driving light, parking and panel light, license plate light, fuel pump, OD solenoid, radio and power plug fuses.

I have chosen in-line carriers as apposed to installing an additional fuse block for the ease of incorporation and hide the additions. This, however, has required that I also create a directory of fuse power, coverage, and location as an assist for my ageing memory.

Hope this helps,
Ray (64BJ8P1)

 

[Jerry]

I added an additional 12 also. Makes me feel that the car is a little safer with the circuits.
Jerry BJ8

 

[Healey_Z]

Hi Healey Z,
Keep in mind that when the Healey was designed and manufactured, thin wiring gauge was up to supporting the low draw of all electrical components provided and the very few options commonly available.
Hope this helps,
Ray (64BJ8P1)

My concern is not when everything is operating properly, or if something is added to the system. Fuses are there for protection when something goes wrong. In the event there is a short to ground, which will go first, the 35 (US amp) fuse or the insulation of the thin gauge wire?

 

[BobFrisby]

There are many less-than-optimal design features on our beloved cars, but I have to agree that the "two-fuse" setup is particularly notable. It's a pet peeve of mine.

I went to my nearby NAPA store, and got a very tidy little fuse box, holding ten of the newer ATO "blade" fuses. It fits pretty much where the original did. I ended up using seven of the fuse slots, and have spares in the other three.

Bob Frisby
Boise, Idaho
'62 BT7 tricarb

 

[TimK]

I have an 8 circuit box and three inline fuses. The most critical is the one for the rear light circuit (red wire powering the tail lights and license plate light.)

 

[Keoke]

This is my first British car that I have owned. I just can't see how system that has only two circuits, one with a 35A fuse, and one with a 50A fuse is the best design.

Amazing isin't it!!!! But here we are 40 some years or more later and the cars are still around.-----Keoke---

 

[Michael Oritt]

I have two six-circuit fuse panels installed on my 100. One panel is for circuits that are hot all the time such as fog lights, head lights, (yes I know that some of you think this is a bad idea but see below for my reasoning), side/license plate lights, horn and auxiliary fan while the other panel is for circuits that are switched by the ignition--turn signals, fuel pump, brake lights, radio, auxiliary hot spot, etc.

To me fuses are used to protect the wiring as well as the appliance. If a headlight goes to ground and pops a fuse one is way better off than if the wiring circuit is destroyed: In the first case one can hopefully find the defect in the circuit, repair or bridge around it, replace the fuse and go on one's merry way whereas if the wires are burned up a repair will be infinitely more difficult, plus the real risk of fire is greatly increased.