Preventing fires, to "FUSE or Not to FUSE"?

[kkaa]

After reading the "fire extinguisher thread", wanted to be as proactive as possible about stopping them before they start. If most begin with overloaded circuits and wiring, which are the best circuits to place inline fuses? I bought a handful of them from Moss and wanted to ask which are the best?

Wipers, horn, dash lights, ......

 

[andrea]

To wiper dash lights you must add the fuses on tail light, and head light, on the OD wire that came to the solenoid 10/15AFuse(I learned my self the lesson), at the plate rear light -
NOTE: the horn have high absorption Fuse 30A are the minimum
I have find on e bay one sort of spade in line fuse, that have a LED that go ON when the fuse is burn

 

[Brinkerhoff]

First off , make sure your existing wiring harness is in PERFECT condition by doing a thorough visual exam. Check all the bullet connectors for cracked insulation and exposed bullets. If the harness is old or has been spliced , I'd replace it.
The only deviation I've made to stock is to add an inline fuse to the running lamp circuit ( red , lh side of boot) to protect the harness in case the license plate lamp is broken which could short out the entire circuit.
I'm more concerned with one of the braided fuel lines failing and causing a fire than I am about an electrical fire, but I mostly keep a fire extinguisher handy for reasons I can't think of.

 

[Patrick67BJ8]

After reading the "fire extinguisher thread", wanted to be as proactive as possible about stopping them before they start. If most begin with overloaded circuits and wiring, which are the best circuits to place inline fuses? I bought a handful of them from Moss and wanted to ask which are the best?

Wipers, horn, dash lights, ......

I bought this Fuseblock from Charlie Hart for my BJ8. He also sells a "7 Fuse" Fuseblock for the early cars. I have a 5-Speed Trans so I didn't need a OD Circuit Fuse. I highly recommen that you put an inline fuse for the licenes plate and tail light wiring in the trunk/boot area.

I burned up my original wiring harness back in the '70's because the OD circuit wasn't fused. I also had problems with the center harness melting because the tail/license lights weren't fused.

 

[Keoke]

Properly fusing a circuit can minimise the potential for failure.
However, there are some cases where isolation will improve things over the use of fuses.

For example the lighting switch can be relieved of a heavy current drain by using a relay between the switch and the lighting circuits. Properly sized fusing can then be installed in the lighting circuits.

 

[MikeAH100M]

Saw the note about the license plate lamp short potential problem and the need to fuse. My BN2 had the license plate lamp removed. I am looking for an original replacement (new ones are too cheap - thin steel and plastic lens). In the meantime, is it OK just to cap the wires or should I do something else with them?

 

[Keoke]

Saw the note about the license plate lamp short potential problem and the need to fuse. My BN2 had the license plate lamp removed. I am looking for an original replacement (new ones are too cheap - thin steel and plastic lens). In the meantime, is it OK just to cap the wires or should I do something else with them?

Yes that is OK provided that you insulate each one at the end then jointly cap the ends.

 

[RAC68]

When considering that very few electrical components were originally fuse protected, adding fuses to vulnerable circuits seems a no-brainer to me.

Over the years, I have upgraded wire gauge where I have added additional circuits and used relays to cover some high amperage new or upgraded components. I have also added fuses or circuit breakers to protect many of the unprotected components (i.e. Head/running lights, OD circuit, fuel pump, etc.) and even have added smaller fuses to cover some individual components within the circuit protected by the original box’s 17 amp fuse (the 35 amp fuse still covers the horn but will eventually install a relay to reduce original line draw as well).

Although many have increased the number of circuits protected through the use of larger or additional central fuse blocks, I prefer the use of individual in-line fuses. In-line fuses allow me to add protection for specific circuits, sub-circuits, and individual components, without having to route through/to a central location. Additionally, each fuse has been sized to address the specifics of coverage and, where a failure takes place, minimizes component or operational loss to a device. However, since many of the fuses are concealed to maintain an original look, I have documented fuse location, size, and coverage through the creation of a Fuse Director.

I very much agree with Keoke in the use of relays to reduce amperage on older original harness wiring when adding and/or upgrading components (i.e. halogen head lights, driving lights, modern radio systems, cold-air duct fans, etc.). As an example, adding relays for headlight control reduces original wiring to relay switching amperage while carrying higher amperage through the relay on new, appropriately sized, wiring to the higher draw component/s.

Although some may prefer complete originality, I definitely recommend adding additional fuse protection if you intend to actively use your Healey.

All the best,
Ray (64BJ8P1)

 

[AUSMHLY]

Very well explained Ray.
I upgraded my headlights to halogen and did not upgrade the wires associated with them. There are kits available to do that if. Shortly later, the headlight toggle switch fried. That's how I found out I needed to install a couple relays in line. As mentioned here, add a fuse in inline, in the boot for the license plate light.

 

[kkaa]

This is super helpful. I just purchased 5 of these inline fuses from MOSS. https://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=79454&SortOrder=10

Which 5 circuits would you top the list with first? Im thinking following Ray and going "Head/running lights, OD circuit, fuel pump, horn, and wipers"?

 

[AUSMHLY]

This is super helpful. I just purchased 5 of these inline fuses from MOSS. https://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=79454&SortOrder=10

Which 5 circuits would you top the list with first? Im thinking following Ray and going "Head/running lights, OD circuit, fuel pump, horn, and wipers"?

License plate wire I'd say should be #1. If it shorts, I believe the cars shorts out.

 

[Hot Wings]

If one is interested in maintaining an original look but still want to prevent damage to the whole harness due to one overheated wire, this might be a place to consider a fusible link. They aren't as easy to test and replace as a fuse, but they hide well in a wire bundle and don't blow unless there is a continuous problem.

 

[healeyblue]

wrong thread
Jim

 

[RAC68]

Hot Wings,

I was under the impression that when a fusible link does blow, it will create high heat and (sometimes) sparks. If put in or close to a bundle of wires you may incur additional damage. Please correct me if I'm wrong as I had previously planned to use one in the line from alternator/generator to headlight relays but opted for a circuit breaker.

All the best,
Ray (64BJ8P1)

 

[Hot Wings]

Hot Wings,

I was under the impression that when a fusible link does blow, it will create high heat and (sometimes) sparks. If put in or close to a bundle of wires you may incur additional damage. Please correct me if I'm wrong

Your not wrong. Some do exactly that. Ones with better insulation, likely Tefzel or similar, have better manners. Sizing a fusible link isn't an exact science. It depends on how many conductors are in the bundle, how near the surface the link is and the ambient temperature. Short of some exotic FEA simulation the best we can do as amateurs is use some basic charts and rules of thumb. Even if it does damage some of the bundle the damage is likely to be far less than if the whole conductor was acting as the fuseable link.

The coil/choke heater wire on old VW's is also unfused. I've had the pleasure of having one short out and melt the main harness some where near Bakersfield Ca. Swapping a wire from the tail light got me to a parts store where I bought a roll of wire and duct tape. Ran the wire over the drip rail to the coil and returned the tail light wire to the it's primary task, which fortunately still worked, and managed to get home to Wyoming where I had to replace the main wiring harness.

I'm one of those nasty guys that doesn't really care about being period authentic. I'd rather have something to drive that I don't have to worry about mechanical failure or burning up. Fusable links are way down the list for my personal vehicles. My Sprite will have circuit breakers, Polyfuses and relays - solid state if possible.

I'm also a bit of an aberration in that I never had any trouble with Lucas electronics on my Sprite or MG's.

 

[andrea]

The only trouble that I have experienced is the semi-melt of the OD harness - I have put a FUSE on it -BUT in the wrong side(near the OD switch) I have learned the lesson myself, and NOW the fuse are on the wire that came to the solenoid-where the absorption are massive, this avoid the melting or the burning of the relays wires
I have rewired all this sections of harness, and fused it with on line fuse with LEDwith a rearmable fuse

 

[Lotuswins]

kkaa,

Its amazing the limited fusing on these cars, isn't it? Anyways, when I analyzed the circuits on my BJ8, I installed in line fuses, period correct type of course, in the following circuits:
Fuel Pump, white wire at the fuse block 10A
Overdrive, white wire at fuse block 10A
Lighting circuit, brown wire to light switch at regulator 20A
Running and Panel circuit, red wire at light switch 10A
Battery feed to regulator, brown wire replaced with fusible link, 80A

Having an additional fuse at the license plate is okay, but fuse with 5A so it will coordinate with the running light fuse. I simply bought holders from local autoparts stores and installed appropriate connectors on them (insulated if necessary) so I can remove them in the future if I need to be absolutely correct visually. Otherwise, you don't notice them at all. The fusible link isn't in the loom but runs by itself replacing the short wire to the regulator from the solenoid. I also installed a switch on the fuel pump circuit as an additional theft prevention item, hidden behind the dash.

The fuse ratings are for US fuses, as the British ratings are significantly different than ours. Also note that the fuses are there to protect the wiring in the circuit and are sized based on the smallest wire's thermal capablility.

 

[AH.MKII.Restomod]

I bought this Fuseblock from Charlie Hart for my BJ8. He also sells a "7 Fuse" Fuseblock for the early cars. I have a 5-Speed Trans so I didn't need a OD Circuit Fuse. I highly recommen that you put an inline fuse for the licenes plate and tail light wiring in the trunk/boot area.

I burned up my original wiring harness back in the '70's because the OD circuit wasn't fused. I also had problems with the center harness melting because the tail/license lights weren't fused.

Where can you find these Charlie hart fuseboxes?

 

[BLU_HLY]

You can reach me at hartcg@msn.com

Charlie Hart

 

[DerekJ]

The fuse ratings are for US fuses, as the British ratings are significantly different than ours.

Are American amps different from UK amps?!