Testboy TV 455VDE-tester Testboy TV 455 Manual De Usuario

 

 

 
A current flowing into the PE terminal causes a voltage drop on earth resistance, i.e. 
voltage difference between PE equipotential bonding circuit and earth. This voltage 
difference is called contact voltage and is present on all accessible conductive parts 
connected to the PE. It shall always be lower than the conventional safety limit voltage. 
The contact voltage is measured with a test current lower than ½ I

ΔN

 to avoid trip-out of 

the RCD and then normalized to the rated I

ΔN

. 

 
Contact voltage measurement procedure 

* model TESTBOY TV 450 (TYPE B) 

‰

 

Select the

 RCD

 function using the function selector switch. 

‰

 

Set sub-function Uc. 

‰

 

Set test parameters (if necessary). 

‰

 

Connect test cable to the instrument. 

‰

 

Connect test leads to the item to be tested (see figure 5.17). 

‰

 

Press the TEST key to perform the measurement. 

‰

 

Store the result by pressing the MEM key (optional)*. 

 
The contact voltage result relates to the rated nominal residual current of the RCD and 
is multiplied by an appropriate factor (depending on RCD type and type of test current). 
The 1.05 factor is applied to avoid negative tolerance of result. See table 5.1 for detailed 
contact voltage calculation factors.