measurements on a three phase distribution board

[cocko75]

hi can you anyone help i had to undertake measurements on a simulated 3 phase distribution system it had main switch, bus bar then went to 3 sockets we had to take test with all the sockets on and then turn one off and test it all the readings where different L1 L2 L3 and n (3kw) L1 4.87 L2 4.95 L3 4.86 and n 0.2 all sockets on L1 4.84 L2 5.00 L3 0.00 N 4.95 one socket off . do you have an explanation off the difference between the measurements recorded many thanks would be greatful if you had the answer