নিয়ন টেস্টা বা শক করার কারন

Normally 3ta Line
L1, L2, L3
If we measure with
L1 - L2 get 440Volt
L2 - L3 get 440Volt
L3 - L1 get 440Volt
If we measure with
L1 - N get 220Volt
L2 - N get 220Volt
L3 - N get 220Volt

So, if we touch L1/ L2/ L3 the voltage is fixed.
If we touch N then it is Zero(00) normally, sometimes at unbalance load it might be carry some voltage.

Hope you understand.
@md.mynol sir