"Uffe Bærentsen"
Phil Allison skrev:
"JC"

After some repairing at my house an electrician made an error and didn't
connect a neutral on a circuit breaker that was sourcing some electronic
equipment I have (router, switch, alarm).

The repair work was done on Friday and on Sunday, when I tried to access
the
network I found out that all the electronic equipment was damaged and not
firing up (the PSU I suppose).

At first sight, it seems that if the neutral is not connected we wouldn't
have a diff of potential so I don't see how the equipment could be
damaged
but live & earth were ok so I wonder if anyone can explain to me if the
lack
of neutral could have been the cause.


** A disconnected neutral would normally result in no AC power on that
circuit as the earth conductor is not used for carrying load current.

Only if the neutral conductor were common to more than one phase can a
damaging over voltage exist. This may sometimes be the case in the USA,
but
is not permitted in 240 volt countries for domestic installations.

If the neutral wire in the feeder gets disconnected ...

** Clearly NOT the OP's question.


then you will have
random voltages anywhere in the installation.
Voltage will be anywhere between normal line voltage 115V in US or 230V
here in DK and (sqrt3 * line voltage)
US: sqrt3 * 115 = 200V
DK: sqrt3 * 230 = 400V

** In the USA, 120V domestic circuits are fed via a split phase transformer
from a 3 phase, 240V street supply.

Most homes have 240V and 120V power available, the 240V being used for high
consumption appliances.

The 240v is really 120V-0-120V - so a loss of the incoming neutral can
case the supply to go to 240V.


..... Phil