We have an ongoing debate in our company... The ontario Electrical Safety Authority (ESA) recommends using fused test leads for multimeters. A Fluke representative at a recent electrical safety training seminar recommended against using fused test leads. Who is right and why?

I'd really like to understand why they would want fused test leads. Personal protection? Wouldnt a fuse add to the total resistance of the lead?. I have heard of fused jumpers... thats a good Idea.. On most meters the ampere scale is fuse protected. what other scale needs fuse protection?

The further away the protection ,the less effective the protection is.Putting hi-energy fuses at the business end of the measuring circuit,YOUR HANDS!,gives you extra protection.What if your meter is dirty or there is internal contamination as encountered in dirty industrial environments?The arc fault can blow before the meters internal fuse.Yes,there is resistance in the fuse but that is what the REL function on ohms is for.To null out test lead resistance.Consider fused test leads as back up for the meters fuse.

I have no idea why Fluke would not recommend using fused test leads.
A meter can be a bomb when used in harsh environments and any extra protection is well worth it.I think fused test leads with proper ratings are a fantastic safety idea for test equipment users.

Just simply for my own curiosity, I would really get to the bottom of this. The more I ask, the more I learn. I want to hear from Fluke on this. Why would you possibly stray away from fused test leads? This to me isn't a head scratcher, I must be missing something as well. I totally agree with the post by MAZ. Fluke, do you have any kind response to this? And further more, Fluke does not offer fused test leads in their line of product, any particular reason?
Thanks guys,

~76nemo

Thanks for the backup 76 Nemo.I too would like a response from Fluke.
Anyone interested,the fused test leads I use are Silvertronic.Transcat.com has them.I think John Fluke would have liked the idea himself.

Still no response from this, except from MAZ. And as for the post about adding resistance to the circuit, again, you can't disagree with MAZ. The added resistance is way to small to cause any distraction in most circuit analysis. Fluke, we're listening. If you guys can send us some info. that we can't imagine, it would greatly be appreciated. I am one of the people who really enjoys a good debate.
Fused test leads,..... why not?

~76nemo

Here is our opinion on fused test leads:

It is Fluke's opinion that in applications using Fluke name brand instruments, fused test probes provide little if any added protection. Fluke's primary concern is that fused test probes may result in serious shock hazard do to a false voltage reading. A more effective solution is a meter properly designed to handle overload conditions. For the Amp and milliamp functions, Fluke meters incorporate a specifically designed and tested fuse that is effective to 1000 Volts as the full breaking capacity of the system which limits the energy in a manner that is as effective as a fuse located within a test probe.



It is additionally Fluke's position that a fused test probe is potentially more hazardous when used with any DMM for the following reason. It is estimated that over 90% of most electrician measurements use the AC VOLTS functions of a meter. Current measures are generally less than 10%, more probably in the few percentage points. If the fuse in the test probe is damaged and not noticed or properly corrected, then false voltage measurements will occur which potentially create a shock hazard for the user.



For Fluke meters, a damaged fuse within the amps function of the meter does not affect voltage measurements, so the potential of shock hazard due to false readings is eliminated. Note that for the other meter functions such as ohms, Fluke meters are designed to prevent hazard for overload conditions equivalent the maximum AC volts input as stated on the meter. These functions limit the energy by impedance. This opinion on fused test leads is limited to, an only applies to their use when used with Fluke brand test instruments

Duane

Question answered. What Maz and I did not include in our question was taking into consideration that a well experienced electrician was using the fused leads, not anyone who just pulled the meter out of the box, read it's safety limitations and tried to troubleshoot any ol' problem without the knowledge of proper procedures. Again, I love a good debate, and you got me on this is one,.....SAFETY FIRST TO EVERYONE!!!!!!!!
Who am I to question Fluke? I knew there had to be some kind of reason, and you nailed me with it. That's what you get for not thinking out of the box.
Thanks Fluke,

~76nemo

I agree with Nemo,on EXPERIENCE and Dwane on a possibly open fuse.I assumed that multimeter users go by one of the best safety rules I learned the hard way many years ago,TEST YOUR METER ON A KNOWN LIVE CIRCUIT BEFORE MEASURING THE LIVE CIRCUIT YOU ARE TESTING.This checks that your meter,leads,and FUSE in the test leads mentioned are working.
How many guys out there went nuts or even got zapped because of a flakey open test lead?Your leads get bent, twisted, and pulled every time you use them.
The newer leads have very fine multistrand wires that can easily be broken inside the leads insulation where you can't see the damage.
What I do is plug the meter leads into the meter, put the meter in continuity beep test,short the probe tips in one hand,and shake the meter with the leads hanging and bouncing.The beeper in my Fluke 27 will beep off and on sounding the flakey connection.

I agree with Maz. The best way to insure safety is to use what is referred to as the 3 point test method (test known live, test circuit under test, test known live again). This insures that your equipment is good and your meter is on the right function and range and your leads are in the right jacks ahead of the circuit test. This process eliminates the most common measurement mistakes and also verifies your meter and leads are functional.

Duane