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DMM Lead Arc getting voltage from power strip

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DW1961:
Just got a reply back from RockSeed about replacing the fuses.:

Q: Are the fuses replaceable?

"Yes, just buy a universal voltage current fuse but pay attention to the size of the fuse"

He also said make sure the dial is correct for volts amps and AC DC, and I suppose that is because somehow they are doing everything with two leads, instead of splitting it into an dedicated amp plug.

Gyro:
Well if there are any fuses, then he should be advising HRC meter fuses, not 'just universal' ones. I'm still not clear if there are any current ranges on the probes, or just on the clamp. Only the instructions will tell you.

I think you are duty bound to go searching for them now! [Edit: if he says they are replaceable, then they ought to be easy to locate]  :)

I think what he is doing is just giving generic multimeter feedback rather than anything specific to this particular product (still worrying advice on the arbitrary fuse choice though).

tooki:

--- Quote from: DW1961 on July 26, 2020, 08:46:37 pm ---
--- Quote from: edpalmer42 on July 26, 2020, 08:08:42 pm ---
--- Quote from: DW1961 on July 26, 2020, 07:15:09 pm ---
--- Quote from: TheMG on July 26, 2020, 04:53:43 pm ---
--- Quote from: tooki on July 26, 2020, 12:37:08 pm ---Given that the jacks don’t do current measurement, then the most likely explanation is that you inadvertently shorted the probe tips. Either to each other, or across line and ground (since the neutral and ground are connected back at the panel).

--- End quote ---

That would be pretty difficult to do on a north american receptacle. The slots for live and neutral are very narrow, in fact the probes on most DMMs insert very snug into them, which doesn't allow for any side-to-side movement of the probes so there's no way you'd be able to short the probes to each other, at least not without bending them.

It is possible however on poorly made power strips if the probes are relatively long for the probe to poke past the back of the receptacle and through the insulation of a wire, or a grounded chassis, but this would be rather unusual as most DMM probes are not much longer than a standard plug end.

--- End quote ---

The lead tip is about 3/16th longer than the plug spade. I was having a hard time getting a reading in the power strip. I do remember that and it was not like doing it in a wall receptacle, so maybe I did ground it out. It's a very good explanation.

--- End quote ---

That happened to me many years ago with an old 3-way adapter.  I pushed the DMM probe in and shorted to either the neutral or ground.  Quite an impressive light show!

If your power bar is screwed together, pull it apart and inspect it.  If not, unplug it (!!) and then see if you can get continuity to neutral or ground by probing into the hot lead with the smallest insulated wire you've got.  If you do, that power bar is dangerous!  Cut the cable off and throw it away!

--- End quote ---

Excuse my language but FUCK ME. I got continuity. I'm sure that's what must have happened. I had to search a little, but I got it.
(Attachment Link)

--- End quote ---
Thanks for the update!

It'd be interesting to see how the contacts are laid out internally. Clearly they're not designed to be probed, but then again, that's not actually a requirement for a receptacle. Given that it hasn't blown your home circuit breaker, I take it that no shorting occurs when only actual AC plugs are inserted?

ozcar:

--- Quote from: Gyro on July 27, 2020, 05:51:59 pm ---
I'm still not clear if there are any current ranges on the probes, or just on the clamp. Only the instructions will tell you.


--- End quote ---

Looking at the picture of it, I don’t get any suggestion that it can measure current other than by the clamp.

And, somebody specifically asked the Amazon seller “Can this measure current with leads also?” and was told, no, only via the clamp.

DW1961:

--- Quote from: Gyro on July 27, 2020, 05:51:59 pm ---Well if there are any fuses, then he should be advising HRC meter fuses, not 'just universal' ones. I'm still not clear if there are any current ranges on the probes, or just on the clamp. Only the instructions will tell you.

I think you are duty bound to go searching for them now! [Edit: if he says they are replaceable, then they ought to be easy to locate]  :)

I think what he is doing is just giving generic multimeter feedback rather than anything specific to this particular product (still worrying advice on the arbitrary fuse choice though).

--- End quote ---

He said there is no way to get current reading from the leads, only the clamp and only AC. I can ask which fuse?

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