EEVblog Electronics Community Forum

Products => Test Equipment => Topic started by: Maciek on March 22, 2013, 11:52:06 am

Title: BK2790B@ 500V fuses
Post by: Maciek on March 22, 2013, 11:52:06 am
I skimped through the post about DMMs not compliant to their specifications and I am curious about not meeting CAT standards by the BK 2709B DMM. Following the manual part regarding input protection:
"Input Protection 0.5 A/500 V & 10 A/600 V fast blow ceramic fuses".
There is a comment in the post that the meter actually has 2x500V fuses so I am thinking if replacing fuses with 600V version will make it better. I noticed that some meters have their fuses spec'd like e.g. @0.5A/600-1000V & @10-15A/1000V. Does anyone tried swapping in 2809B?  :-/O I am wondering if putting there 600V fuses will make other parts of circuitry blow. Is it a very serious issue? Ideal 61-342 has it marked as minor inconsequence and not following the specs. Thanks in advance for explanation.
Title: Re: BK2790B@ 500V fuses
Post by: tinhead on April 24, 2013, 04:32:22 pm
i got 2709B with fuses exactly as described in manual -> 0.5A/500V and 10A/600V.
Title: Re: BK2790B@ 500V fuses
Post by: Lightages on April 24, 2013, 05:59:39 pm
Replacing fuses with a higher voltage rating is never a bad idea. It doesn't not mean that the meter is now capable of a higher safety rating. It is more than just the fuses. In the case of the Ideal meter the fuse is rated very close to the CAT rating and so I deemed it less and issue than a meter that has little glass fuses rated for 250V when the meter is supposed to be rated for 600V+.

A higher voltage rating on a fuse means it will reliably interrupt a higher voltage whereas a lower voltage rated one will possible still continue to pass current with a voltage applied higher than its rating. Higher voltage fuses are good things and cannot harm your meter.

The BK 2709B had 500V rated fuses inside it with Dave's review (unless I read them wrong) so I prefer to leave this as a warning. It makes it even worse if the meter is being supplied with fuses less than specified on the manual.