Difference between Neutral and Phase

There is only on option here and this is it.

Your neutral/ phase is not properly connected. Check the voltages with the earth terminal.

Then trace back the wires, somewhere you will see a loose connection (likely) or the wire itself is underrared for the current (less likely).

Also check-up whether it ahs something to do with the number of appliances on your second floor switched on at the moment.

BTW: Though it may be tempting, do not use the earth wire in place of neutral. Check and remove the fault.

If he is in the US then the neutral and ground are bonded at the panel

Noshorts,

Please replace "are" with "Should be"... There have been many cases where the Earth (Ground) to Neutral bond is faulty or missing entirely due to age, poor instalation etc.

It would be one of the first places to look.

Regards,
Sapper.

dinesh.jprsharma

1) trace the wires n see if u find any insulation faults or earth faults (contact an electrican).

2) the load on the second floor (computers) generate third harmonic currents which add up wit neutral currents. so it can cause vltg variation ......

if you are reading a potential differance it could only mean that you are reading a different phase from the panel. There could also be a restive load on the neutral i.e. loose joint. On 120 v systems I measured the voltage as high as 128v and as low as 112v and there were no problems. What you really need to watch out for is an unbalanced load across phases because the neutral will carry the unbalanced load. I just had a buddy of mine call me last week and ask me why he got shocked off of a neutral and after he checked he found a 15A differance.