"protective" boots on electrical terminals

[LaunchD]

I have a question regarding the rubber boots that are found on the positive terminals of alternators and starter motors.

Do we really need them?

Currently, I have seen instances where the boot collects more dirt and water than it shields. Over time, the boots become brittle and have to be cut off anyways to inspect and/or remove the nut under the boot. After this happens, there is no boot on there until the cable is replaced.

However, the boot does help in the prevention of shorts to ground (if another cable or tool comes in contact with it). And it is also a visual indicator that the terminal/post is usually the positive power supply.

From what I can see...

Reasons to use boot:
Sometimes protects the terminal from the elements.
Prevents shorting to ground (accidental)
Visual indicator of main power to component.

Reasons to not use the boot:
Sometimes collects dirt/water and terminal corrodes quicker.
Technicians can visually inspect the terminal easier and more effectively.
Over time it breaks off or is cut off by a technician anyways (so what is the point in the first place?)

I would appreciate any thoughts or tips. Are there SAE or IEEE standards?

 

[evelrod]

I think you have it covered (pun intended)!
I see the covers as okay to prevent incidental shorts from stupidity or carelessness...and to cover DOT rules, perhaps.

I use covers on my batt terminals and my alt terminal because the racing club rules say a must...so, I do!

My 1930 Model A Ford is now 77 years old with NO covers and it's doing just fine, thank you very much.

Rod

 

[MikeHalloran]

I've run cars with and without. An undamaged boot keeps road brine out of the connections, and they don't corrode as quickly or as severely.



Mike Halloran
Pembroke Pines, FL, USA

 

[LaunchD]

Thanks for the input, thus far.

I should add that this decision (to use them or not) will affect a fleet of over 1000 city buses.

Dave

 

[MikeHalloran]

... and preventing one corroded/ broken stud will pay for all the boots.



Mike Halloran
Pembroke Pines, FL, USA

 

[NickE]

Also in an accident (DOT rules here I'm sure) the boot may prevent a huge dead short to ground while fuel spills everywhere cause the hood has impacted severely onto the terminals.

 

[LaunchD]

Thanks for the help
Your input has been useful in my decision.

Dave

 

[GregLocock]

I think Nick's on the right track.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[evelrod]

Nick and Greg.

"...DOT rules, I'm sure...". Yep, I agree...at least in that part.
Having had a couple of 'incidents' (race related) where I had up close and personal experiences with these darling little rubber thingies...They ain't worth crap at protecting an electrical terminal from a dead short when a big, honking chunk of somethig or other whacks the crap out of it---as we usually see in crashes, hey?

Rod

 

[evelrod]

Nick and Greg, part 2.

You can never underestimate the stupidity and carelessnes, indeed, pure ignorance, of the folk that purchase and operate a motot vehicle on public roads. The little 'rubber thingies' (my termonology) don't even measure up here...I watched an 'older gentleman' check to see if his battery had a charge by peeling back the OEM cover on the batt and solidly shoving an open set of pliers hard against both terminals...It was hot. Trust me, it WAS hot! I guess I'm rather insensitive, ILMAO!!!

Rod

 

[IceStationZebra]

IMHO all they are good for is preventing the accidental shorting by a mechanic working near by. Even though I should know better, I have done it once or twice.

ISZ

 

[RossABQ]

As cramped as cars are, it is very easy to get a wrench across an alternator terminal. As far as battery terminals, I have seen someone slam a hood on a car that "apparently" had a replacement battery that was marginally taller than OEM, and the Pos. terminal shorted to the hood. Before he figured out why the hood's paint was turning brown and peeling, the battery blew. Similar could happen in an accident. Probably not a factor on a bus...