British fuses vs American fuses

[Tinkerman]

Relaxing yesterday evening after a long day with SU carbs I and was going through tne August/September issue of the The Vintage Triumph, official publication of The Vintage Triumph Register. In an artical on fuses the Author stated that "The British Standard that Triumph used, rated fuses by the current that make them blow "Instantly". The American (and now international) Standard rates fuses by the current that they will carry forever."
I don't know about any of ya'll but when I will be doing the electrics on my TR, I have would looked at the literature and if it said 50 amp thats what I would have put in, purchased at the local auto parts shop. That would have meant fry city for my LBC. According to the artical it would burn whe wires and, and most probably, start a fire. The author included a table that listed the British Amp Capacity and the American made Buss fuse equivalent. As follows:

BRITISH BUSS
50 25
35 20
30 15
25 15
20 10
10 5
5 3
Thought it was important enough to pass on. He did not say if and when the international standard was adopted in England, so someone might know and can pass that info on.
Cheers, Tinkerman

 

[Guest]

Point well made, Tink. The article in the VTR mag was right on. If you are wiring your TR3 with an authentic British Wiring harness (ie, stock) then stick with the Lucas fuses. Even the wires in an authentic harness are different than the standard automotive wires that you would get from NAPA or other. I believe they use small gauge copper wire and more wire per bundle than the comparable 10,12,14,etc. gauge wires that are commonly sold for automotive wires here.

A good explanation of this process can be gotten by calling British Wiring and talking to Leslie, co-owns the company with her husband.

Also, get their bullet connector pliers for all your authentic bullet connectors. I crimps & solder everything. Much better than spade connectors, and authentic.


Bill

 

[philknight]

I picked up a set of bullet connector pliers and they are the coolest tool ever, and make bullet connections a cake walk. Is Leslie the nice lady who answers the phone with the British accent?

 

[Guest]

[ QUOTE ]

Is Leslie the nice lady who answers the phone with the British accent?

[/ QUOTE ]

One and the same. She's half the fun of doing business with BW. Nice gal.



Bill

 

[Tinkerman]

Thanks for the tip Bill, I will call them in the morning. And yes I do have a stock harness.
Cheers, Tinkerman

 

[Keoke]

Hmmm, I been wondering why those British Wire harnesses keep burning up wid British fuses in them? I guess I better call Leslie and find out.---Keoke- /ubbthreads/images/graemlins/frown.gif

 

[Tinkerman]

Ya Know I must have been really relaxed when I wrote this post. I could not figure out why artical looked wrong. It should be article. And as I read the post the numbers are all jammed together. Not the way I had typed it out. The smaller numbers are the BUSS fuse numbers. I'm sure all of you have figured this out, but you never know......
Cheers, Tinkerman

 

[JamesWilson]

[ QUOTE ]
I'm sure all of you have figured this out, but you never know......

[/ QUOTE ]

This gets re-discovered regualrly and posted about...

but its exactly the sort of thing that needs publicity for people new of LBCs, British wiring and Lord Lucas...

 

[Guest]

[ QUOTE ]
Ya Know I must have been really relaxed when I wrote this post. I could not figure out why artical looked wrong. It should be article. And as I read the post the numbers are all jammed together. Not the way I had typed it out. The smaller numbers are the BUSS fuse numbers. I'm sure all of you have figured this out, but you never know......
Cheers, Tinkerman

[/ QUOTE ]

It's a good thing you didn't post this on the MG forum. I can just hear thousands of little Morris Garage cars bursting into flames all over the country because of your typo. Hehehe /ubbthreads/images/graemlins/devilgrin.gif

Bill

 

[martx-5]

What it really boils down to, is that the British (Lucas) fuses are TWICE the rating of the Buss fuses. IOW, if the Brits want a 25, we go buy a 12.5. Since we can't get a 12.5, we go to the next highest equivalent...15. /ubbthreads/images/graemlins/cool.gif
/ubbthreads/images/graemlins/cheers.gif

 

[hondo402000]

I did my self a favor and replace the old fuse block with a new style fuse block with extra fuses. It screwed into the same spot and replacemt fuses are easy to get

 

[StagByTriumph]

Re: British fuses vs American fuses - WARNING!!

Hello All,
First I must warn you /ubbthreads/images/graemlins/nonono.gif, the VTR TVT article was published by someone who knows nothing about British or automotive electrics - that being Mike Cook, TVT Editor. Giving the benefit of the doubt, it was probably written with a good intent, but with potentially dangerous results.
However, the fact remains that this article was dangerously and irresponsibly cut-n-pasted with information from several sources, and it contains errors that could burn your car to the ground. /ubbthreads/images/graemlins/shocked.gif
I DO NOT ENDORSE THAT ARTICLE, it was published and edited without my permission.
I would hope that VTR would perform some more research, ask the people who researched the "referenced articles" and ARE Electrical Professionals to make corrections and then publish something that is correct.

The problem is mainly related to Triumphs outside of the UK and Europe, mainly those in North America since we have different automotive electrical standards than the UK and Europe:
1. British Automotive wiring is not the same size nor current carrying rating as US automotive wiring;
2. British Fuses are "dual rated" with a current carry capacity (lower number) and an instantaneous open (blow) rating (upper number) with anything inbetween based on a time/current curve to open.
3. USA or UL fuses are rated only at a current carry rating without opening (blowing), which by North American Standards is generally +/- 10%. So UL fuses could easily carry 110% of the labeled current all day and night long generating HEAT, where it probably should have opened after some time carrying 110% current if it was a British Standard Fuse.
4. You should NEVER substitute a UL rated Automotive Glass Case (AGC) fuse for a British Standard Fuse, they ARE quite different in the way they function. Even if you know what you are doing, the person you sell your car to may not, and an error in fuse sizing can cause a serious car fire.

The fuse specifications for our LBC's are for British Standard fuses protecting British Standard wires. British Standard fuses ARE available in the USA from various British Parts suppliers IF you ask.

Anyone telling you to substitute a UL fuse for a British Standard fuse is being negligent and irresponsible, and if they are an Electrical Professional, they may even be criminally negligent. This is why I do NOT endorse that article, it has my name in it as though I recommend such practices - I do NOT! /ubbthreads/images/graemlins/hammer.gif

Some sources for the correct British Standard Fuses are:
British Wiring in Illinois,
The Roadster Factory in Pennsylvania
just to name a few.
You can also buy British Standard fuses from the UK and any of the British Car parts suppliers.

Although this is not an all inclusive response, I hope this helps by stopping at least one person from buring their LBC to the ground in a pile of ashes. I have SEEN it HAPPEN! /ubbthreads/images/graemlins/cryin.gif

 

[Dave Russell]

Re: British fuses vs American fuses - WARNING!!

Hi Glenn,
I think you are getting a bit too excited.

The typical Lucas Brit. Standard/IEC fuse rating states that a 17/35 fuse will carry 17 amps continuously & blow within two minutes at 200% of rated current or 35 amps, not exactly instantaneous. It also states that the fuse must not open in less than one hour at 125% of rated current, must carry about 21 amps.

While the list mentioned above is not perfect, it's not too far off. However I believe the stated Buss fuse at 20 amps is a bit large to substitute for the Brit. 17/35 & the Buss AGC15 is a better match. Maybe the fact that the 15 amp Buss fuse will actually carry about 30% more than it's rating was overlooked? A pretty safe bet would be to use an AGC fuse of the next lower rating than the Brit. lower number.

The Bussman published fuse time-current curve for the AGC15 fuse shows a continuous rating of around 20 amps. Not far off from the 17 amp, actual 21 amp, Brit. fuse which states that it must carry 125% of rated current for one hour. From the same curve, Buss shows a blow time of 1.5 seconds for a load of 30 amps. Likely faster than the IEC spec. of "within two minutes at 35 amps" (200%). Even a smaller Brit. wire size will carry 35 amps for long enough to blow the fuse.

All simple fuses operate on the same basics. That being the time to melt is a function of amp squared seconds, neglecting the effects of ambient temperature. No matter if they are Brit. or USA. They are not "quite different in the way they function".

As far as leaving a trap for the next owner, if an AGC15 blows & the next owner substitutes another AGC15, no problems.

I really think that in the past,this topic has already been beat to death.

I guess to be safe, folks that don't know about electrical stuff should always use the "correct" Brit. fuses if possible. I even have some old Lucas fuses that are only marked 50 amp, no lower number.

Regards,
D

 

[Keoke]

Re: British fuses vs American fuses - WARNING!!

Well Dave, I think they be safe one way or the other as the critical circuits wich will burn the car to the ground have nary a fuse in sight!----Keoke- /ubbthreads/images/graemlins/yesnod.gif- /ubbthreads/images/graemlins/laugh.gif

 

[piman]

Re: British fuses vs American fuses - WARNING!!

Hello Keoke,

if you look at some 60's British Ford cars, they have no fuses whatsoever (except maybe an in line for the radio, De Luxe model of course), critical circuit or not.

To be realistic there are few components that will malfunction and cause an overload, 'A' Type overdrive solenoid being one, but I believe that the cable size is large enough to carry the full 'pull in' current anyway.

Most malfunctions which blow a fuse tend to be earth faults and the fault current is very high so blows almost any size fuse.

Alec

 

[Keoke]

Re: British fuses vs American fuses - WARNING!!

Well Piman, if that be the case why all these OVD harness be burning up!?---Keoke- /ubbthreads/images/graemlins/grin.gif

P.S. The pull in current isn't enough to warm a fly. Just a few "Jule's" me thinks.

P.S. 2: If the OVD Solenoid cocks up it will pull 19
Amp's of current and the harness will become the fuse!- /ubbthreads/images/graemlins/yesnod.gif

 

[StagByTriumph]

Re: British fuses vs American fuses - WARNING!!

[ QUOTE ]
Hi Glenn,
I think you are getting a bit too excited.


[/ QUOTE ]

Not when I have put out three fires in other LBC's due to improper fuses being used. I hate when that happens /ubbthreads/images/graemlins/shocked.gif

BTW, the BS standard used back then (early 60's) is not the same as the IEC Standard for European Union fuses today. /ubbthreads/images/graemlins/nonod.gif IEC is getting away from dual rated fuses. The British and French are always in a pissing match on who's standards to use.

[ QUOTE ]

I guess to be safe, folks that don't know about electrical stuff should always use the "correct" Brit. fuses if possible. I even have some old Lucas fuses that are only marked 50 amp, no lower number.

Regards,
D

[/ QUOTE ]

Now that is advice I can live with. Did you know that just because a Lucas fuse is labeled "Lucas", it does not mean it is a British Standard fuse? Lucas made fuses for all markets, including North America. I bet that information just gave you a warm fuzzy /ubbthreads/images/graemlins/yesnod.gif ??

The root problem is that a LBC owner who does not know electrics and blows a fuse on a trip, drives into NAPA, Pep Boys, Kragen/Checker, Auto Zone, Advance Autoparts and the parts guy looks at a Lucas 50 amp fuse, gives the LBC owner an AGC 50 amp Little Fuse, not a 25 amp.
This is not a problem until there is a fault in that circuit that should have been protected by that fuse - then what?
The magic smoke escapes from the wire and sometimes, just sometimes, starts a car fire.

 

[Geo Hahn]

Re: British fuses vs American fuses - WARNING!!

[ QUOTE ]
...I believe the stated Buss fuse at 20 amps is a bit large to substitute for the Brit. 17/35 & the Buss AGC15 is a better match...

[/ QUOTE ]

FWIW - I have long used a 14amp Buss fuse in the TR3. Nice thing about that size (at least among the ones I have found) is that it is slightly smaller than the 20 amp -- very similar in physical size to the smaller Lucas 35amp.

Sure, if someone isn't clear on the different rating systems than they should just order a fuse from TRF or whomever.