Weird electrical problem

Page 2 of 2  
Alexander Galkin wrote:

Are a bunch of your wires running for long lengths in parallel through the same holes in the studs? It is a long shot, but it might be inductive coupling. Were the circuits that had the breakers still on loaded? That is, were lights or other things on such that the circuits had current flowing in them?
Typically, if Romex-style cable is used the return current in the white wire should cancel the field from the black wire and thus there shouldn't be any significant net field to affect adjacent wires, however, sometimes strange things can happen.
Matt
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Alexander Galkin wrote:

Hi, Tried using both DVM and analog meter? Tony
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
message

was fine, I had

drywall. I have

was wrong.

found a very

following wiring

recessed lights 65 W

V / 20 A, 2 220

circuit
breaker while all

problem were on we

of other

switching off all new

be.
weird residual

voltage is being induced in the disconnected circuit due to its close proximity with live current carrying wires.. the electro magnetic effect created by an conductor.
I am currently revamping a 20 year old control system, no big deal, a few pumps, a boiler and a cooling tower... very nice control job these guys put in... 24vdc, the wires are all bundled nicely.. and the job as worked more or less fine for 20 years with a few bugs no one has figured out.
in checking out I noticed all kinds of 2 to 9 volt reads in open circuits. Fortunately there were no electronics or logic controllers in this old system so the stray voltages were not sending bogus signals to the electronics... but at 9vdc, and sometimes AC.. and relays operating at 24vdc... I think they got a little sticky at times and is the source of the unfathomable bugs.
However moi here is adding a PLC to the mix (dinky solid state computer that does simple logic functions, 256 various combinations)... and If I am not careful the wiring I install will be next to higher voltage conductors that will induce current in my PLC feed wiring.... and the PLC will go nutz... and produce all sorts of bogus output.
a bad thang.
Fortunately I am putting this low voltage wiring in a separate cabinet and not bundling the wire as the other stuff is bundled so I wont get stray signals.
I almost decided to run some 110 vac transformer power wire in the same conduit as the 24 vac control and alarm wiring some of which would go directly to dialers.. no relay in between. that could have been a mess because both the dialers and the PLC are AC voltage.. *any& AC voltage... so say 15vac or 120 vac signal is acceptable as an input to the plc. That would have been messy. The instructions with these particular devices even say you can use DC inputs over a wide range to trigger the PLC switching actions even though they are rated for AC only and sell a strictly DC unit if you want one.
So what does that tell a person? That all those trace stray voltages will create havoc in yer electronic gismo's.
Sigh.
Getting back to your case. Dont worry about it...while there is voltage in the disconnected circuit, its induced and not capable of pushing much amperage, so its harmless in a home wiring sort of scenario/... just a faint distortion to a circuit under load.
Phil Scott

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Phil Scott posted for all of us....

Which would be a code violation.
--
Tekkie

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Following advise I plug-in the load (TV) into one of receptacles. Residual voltage dropped to zero immediately in switched off circuit even when measured by digital multimeter. To verify this I unplugged the TV and voltage jumped to previous ~8-9V. Now I am convinced it is inductive voltage induced by other hot circuit wires running close to the disconnected one. I am calling the electrical inspector to re-inspection.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Site Timeline

Related Threads

    HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.