fluke 16 multimeter

[tsunami]

Just replaced my old multimeter with this new fluke 16. This one has a "V-check" feature on it.
what exactly is this for and what damage can it do when checking cuircuts pcbs etc . the leaflet mentions it can be used to eliminate "ghost" voltages what does this mean? As a plumber (go easy on me please!)i mainly use my meter to fault find on boilers and heating systems.

 

[Spark123]

It appears you can put a 2kohm low impedance across the test probes which in the event of voltages such as capacitive coupling in a 2 way lighting circuit will drag the voltage down giving a more accurate result.
I suppose you can get "ghost voltages" on 3 wire thermostats too but don't qoute me on that.

 

[tsunami]

thanks for the reply. Im more bothered about what it will do to pcbs when checking boilers. What exactly deos this low impedance part mean, as i say im just a plumber and my old meter was a more simple one. Does this meter actually put 2k ohms through the tested cuircut and therefore may cause damage if so what?

 

[Spark123]

A normal multimeter has a high impedance which is why you can get false readings owing to capacitive coupling, a low impedance will pull the voltage down hence reducing the risk of "ghost" voltages. A 2K resistance across a 240v supply will cause 120mA to flow. It depends on the actual PCB as to wether it can handle this, do you test the PCB with it powered on? What voltages are present?

 

[tsunami]

most pcbs i test are covered by a 2 amp fuse.

 

[Spark123]

What are you testing though, i.e. is there a supply out to the thermostat sort of stuff? Are they powered up when you test?

 

[tsunami]

yes i do test live on boilers and room stats etc. mainly combis. On the pcbs i only fault find to the board its self i.e. power in, power out, not fault finding on the board itself.

 

[Spark123]

I can't see it being a problem to the PCB if you are only looking at supplies, the 2K low impedance will probably be a good thing when testing the switch returns as it should ground out any coupling issues. Maybe run it by the plumbing forum for a second opinion.

 

[tsunami]

cheers for that spark! you know what its like when you get something new and theres stuff on it you dont understand (or probably need!). my boss replaced my old meter with this one when my old one went west. where are you at by the way cos i'm from Cumbria too, Whitehaven.

 

[Spark123]

I'm a little bit further south, close to Barrow!!