help analysing my main AC power

milen007 · 27th June 2008, 01:20 PM

just realise to day that my ground got voltage. this voltage is present when shielded power cable is plug into the outlet.

when the hifi is unplug
voltage between :
hot and N is 208v ac
N and ground is 0v ac
hot and ground is 202v ac

when the hifi plug into the outlet but all the unit is off (just standby)
voltage between :
hot and N is 209v ac
N and ground is 69v ac
hot and ground is 157v ac
ranges of dc voltage between N and ground is 0.7 to 0.9 mvolt. the same with dc voltage between hot and Ground. they range the same

my question is:

is this normal that the ground have dc and ac voltage when my units plug in (standby) the outlet?. i never know this until today i get the voltage detection pen that has LED to check the voltage. and the LED is light up

is my ground working properly? i think its not. as it should eliminate all the ground voltage.

opinion? thanks Erwin

milen007 · 27th June 2008, 04:34 PM

My main voltage is 240v.

its in the evening and its drop alot. then later now at night it come back to 220v. though i have voltage regulator that stabilized the voltage.

investigating further, its only happen in the duplex of the plug in outlet and in the power distributor only.

the other outlet thats few meters away is normal. why is this happen? how to correct this?

milen007 · 27th June 2008, 05:40 PM

i am in Asia. the voltage is 240v. my ground is 30m drill to the ground with 1 meter copper rod at the end. with at least 5 AWG to the panel. which then getting smaller to 14 or 15 AWG in the house circuit.

Mooly · 27th June 2008, 05:51 PM

Is it possible that what you are seeing is caused by filter caps in any equipment that are connected across L-E, N-E, L-N that are passing a small AC current into the ground wire.
Here in the UK we would not see this as neutral and earth are at the same potential ( Trying to choose my words correctly here and just to add neutral and earth are NOT ONE AND THE SAME).
Could this be what you are seeing, and this may not be a problem.

AndrewT · 27th June 2008, 06:01 PM

Hi,
it sounds like there may be a fault in the continuity of the earth or neutral wiring.
Get an electrician in to check over your distribution wiring.

milen007 · 27th June 2008, 06:21 PM

molly, its less likely being caused by the components.

i plug the PC on power distributor with no cable connectiong to the distributor has already causes this problem.

AndrewT, thats very likely. what other easy check to make sure its connected to actual ground in the panel?

there should be no voltage at all if properly grounded right?

milen007 · 27th June 2008, 07:15 PM

just pull an extension cord from the plug that is diffrent breaker in the panel. same thing happens.

neutral and ground voltage is increasing with the more shielded cable being plugged in with no component or unit attached

while hot and ground voltage is decreasing with more shielded cable plugged in which same case as above. only the PCs.

this is new house wiring. havent actually check if my ground work properly. i might be the whole house is not grounded.

opinion?

27th June 2008, 01:20 PM	#1
milen007 diyAudio Member Join Date: Dec 2007	help analysing my main AC power just realise to day that my ground got voltage. this voltage is present when shielded power cable is plug into the outlet. when the hifi is unplug voltage between : hot and N is 208v ac N and ground is 0v ac hot and ground is 202v ac when the hifi plug into the outlet but all the unit is off (just standby) voltage between : hot and N is 209v ac N and ground is 69v ac hot and ground is 157v ac ranges of dc voltage between N and ground is 0.7 to 0.9 mvolt. the same with dc voltage between hot and Ground. they range the same my question is: is this normal that the ground have dc and ac voltage when my units plug in (standby) the outlet?. i never know this until today i get the voltage detection pen that has LED to check the voltage. and the LED is light up is my ground working properly? i think its not. as it should eliminate all the ground voltage. opinion? thanks Erwin

27th June 2008, 06:01 PM	#5
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, it sounds like there may be a fault in the continuity of the earth or neutral wiring. Get an electrician in to check over your distribution wiring. __________________ regards Andrew T.

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27th June 2008, 04:34 PM	#2
milen007 diyAudio Member Join Date: Dec 2007	My main voltage is 240v. its in the evening and its drop alot. then later now at night it come back to 220v. though i have voltage regulator that stabilized the voltage. investigating further, its only happen in the duplex of the plug in outlet and in the power distributor only. the other outlet thats few meters away is normal. why is this happen? how to correct this?

27th June 2008, 05:40 PM	#3
milen007 diyAudio Member Join Date: Dec 2007	i am in Asia. the voltage is 240v. my ground is 30m drill to the ground with 1 meter copper rod at the end. with at least 5 AWG to the panel. which then getting smaller to 14 or 15 AWG in the house circuit.

27th June 2008, 05:51 PM	#4
Mooly diyAudio Member Join Date: Sep 2007	Is it possible that what you are seeing is caused by filter caps in any equipment that are connected across L-E, N-E, L-N that are passing a small AC current into the ground wire. Here in the UK we would not see this as neutral and earth are at the same potential ( Trying to choose my words correctly here and just to add neutral and earth are NOT ONE AND THE SAME). Could this be what you are seeing, and this may not be a problem.

27th June 2008, 06:21 PM	#6
milen007 diyAudio Member Join Date: Dec 2007	molly, its less likely being caused by the components. i plug the PC on power distributor with no cable connectiong to the distributor has already causes this problem. AndrewT, thats very likely. what other easy check to make sure its connected to actual ground in the panel? there should be no voltage at all if properly grounded right?

27th June 2008, 07:15 PM	#7
milen007 diyAudio Member Join Date: Dec 2007	just pull an extension cord from the plug that is diffrent breaker in the panel. same thing happens. neutral and ground voltage is increasing with the more shielded cable being plugged in with no component or unit attached while hot and ground voltage is decreasing with more shielded cable plugged in which same case as above. only the PCs. this is new house wiring. havent actually check if my ground work properly. i might be the whole house is not grounded. opinion?

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