Frequently asked questions


Why doesn't my Proving Unit alow my Voltage Tester to display up to 690V


The PU260 proving unit will limit the amount of voltage it outputs depending on the

load taken by the combi volt. It does this for protection against electric shock to protect

the user, and works in line with the electricity at work regs, (section for the protection against electric shock). If you use the PU260 with a simple voltage indicator with no continuity or buzzer then it would give 690v, as the load from the tester would be very small. With the combivolt the load will reduce the output voltage to about 110v. If the user was using a Fluke T100/T120 (i.e. 6741/6742) then the voltage would be much lower to around 50v. This is because the older units would trip an RCD and hence take 30mA from the proving unit. Anything above 3.5mA would reduce the voltage and the >3.5mA L.E.D

will illuminate. This makes our proving unit safer than any other when used, and protects the operator from the risk of electric shock.
Please be advised that the 
PU260 is designed to output up to 690V depending upon the

load of the voltage indicator used. The unit will limit the available current to 3.5mA to

comply with current regulations for protection against electric shock.  If the load of the

unit on test requires greater than 3.5mA a reduced voltage will be indicated on the

voltage indicator. (DL6780 & DL6790 expect around 100V).


Please click here to download an information sheet on the above