What is the 9v battery lead doing underneath the 11A fuse for the amps mode?
If they thought that was a good routing idea why even bother with a fuse with a 11kA interrupt rating or whatever it is?
My 87V from late 2018 has the battery wires in the same setup. Contemplating the potential current paths, I am not seeing a cause for concern, though.
What is the 9v battery lead doing underneath the 11A fuse for the amps mode?
If they thought that was a good routing idea why even bother with a fuse with a 11kA interrupt rating or whatever it is?
Thanks for sharing.
How old is the 87 line now?
Introduced in the late 80's IIRC.
What for? It does the job, is well respected in the industry and has a long history. Why would you want to jeopardize all of that for some elusive extra sales?
Not much changed over the years (87, 87 III), if you discount the 87 IV which was completely different:
IP30
VFD
Temp
Higher diode test voltage
Extra capacitance range
Slightly better accuracy with a 6,000 count instead of 4,000
That's it!
What is the 9v battery lead doing underneath the 11A fuse for the amps mode?
If they thought that was a good routing idea why even bother with a fuse with a 11kA interrupt rating or whatever it is?
Because the battery leads are sleeved with silicone-impregnated fibreglass which will be rated to at least 1kV?
What is the 9v battery lead doing underneath the 11A fuse for the amps mode?
If they thought that was a good routing idea why even bother with a fuse with a 11kA interrupt rating or whatever it is?
Because the battery leads are sleeved with silicone-impregnated fibreglass which will be rated to at least 1kV?Ok, I just assumed it would be bad design practice, as for example you often have wide PCB cutouts for preventing arc-over.
But here we have a cable literally clamped in the fuse holder (refer to picture: "2.1 DSC03156_.jpg")
I based this off my experience of fuse holders with those stupid series lamps that light up to tell you the fuse failed:
When the manufacturer places them in high energy circuits the whole fuse holder catches fire and melts into a mess.
But granted the wires are not covered in sleeving so I guess Fluke knows what they are doing, it just rubbed me the wrong way seeing that...
Thanks for sharing.
Littelfuse fuses are rated the same, but are somewhat cheaper.
Unless things have changed dramatically recently, all new 87 V meters come with Bussmann fuses.
Are you sure this meter hasn't been tampered with, before you bought it?
A missing O-ring and suspicious fuses make me wonder.
Contact Fluke Germany if you want to find out:
Fluke Deutschland GmbH
Ok, I just assumed it would be bad design practice, as for example you often have wide PCB cutouts for preventing arc-over.
But here we have a cable literally clamped in the fuse holder (refer to picture: "2.1 DSC03156_.jpg")
I based this off my experience of fuse holders with those stupid series lamps that light up to tell you the fuse failed:
When the manufacturer places them in high energy circuits the whole fuse holder catches fire and melts into a mess.
But granted the wires are not covered in sleeving so I guess Fluke knows what they are doing, it just rubbed me the wrong way seeing that...
Are you sure this meter hasn't been tampered with, before you bought it?
A missing O-ring and suspicious fuses make me wonder.
Ok, I just assumed it would be bad design practice, as for example you often have wide PCB cutouts for preventing arc-over.
But here we have a cable literally clamped in the fuse holder (refer to picture: "2.1 DSC03156_.jpg")
I based this off my experience of fuse holders with those stupid series lamps that light up to tell you the fuse failed:
When the manufacturer places them in high energy circuits the whole fuse holder catches fire and melts into a mess.
But granted the wires are not covered in sleeving so I guess Fluke knows what they are doing, it just rubbed me the wrong way seeing that...
I agree those sleeve underneath the fuse is that's smth. what you immediately pay attention to. Not the best design decision. Though while fuse is not blown the potential here on fuse holder clamps is about a couple of mV to the ground due to fuse extra low resistance. So no ways arc can arise here. The only way for arc to arise is to measure high voltage circuits (lets say more than 1kV) and high energy at the same time in order to blown the fuse (lets say more than 30A). Then yes that dangerous voltage would potentially trigger an arc to the battery leads. What voltage we need here to go through sleeve and through battery leads insulation? I guess more than 10kV. I've seen some test on youtube for that particular case (see below). BTW working with so high voltage/energy is out of scope for this meter, its even not a cat. IV I guess.
Though while fuse is not blown the potential here on fuse holder clamps is about a couple of mV to the ground due to fuse extra low resistance.
Thank you very much for the linked video, it prooves well that I was wrong
And thanks for your pictures
- Fuses brand
I've always worked with fuses that cost ~10 cents. So can't complain here. BTW Bussmann costs $50 on Digikey while Littelfuse is $25 (crazy prices anyway, lol). This is where Fluke gets the cost down. Is Littelfuse as good as Buss?