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Author Topic: Tell me I'm not losing my mind  (Read 2199 times)

David Allred

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Tell me I'm not losing my mind
« on: June 04, 2019, 10:36:37 am »

For an exterior building light project I handle the communications for the venue with the electrician of what I needed.
Yada-yada I need 120vac to these 9 locations.  7 on the ground and 2 on the roof. 
I need the an exterior kill switch (for maint) on the hot leg serving all locations.
I need a switch leg inside to the office space for a USB timer relay board, that runs off a PC's clock and powered thru the USB connection.  I want the switch on the neutral leg.
(1st sign of trouble - he refers to the relay as a transformer.  I refer to it again as "a simple switch that just needs a loop out to the exterior junction box" because at the time there was talk of tying into an exist circuit already run outside.  He continued... "you need power run to the transformer, right?"   I correct him again, saying "No", it is 100% powered from the PC's USB cable, no power run needed, just a switch leg.)

Electrical work is completed.  I pop the ceiling panels to connect the USB relay  to the switch leg and there are 2 wire sets.  One marked "Hot" and one marked "switch leg).
I called him up and asked what I was supposed to do with this?  Was the Hot run just a spare in case I wanted a power source.  His reply, "That's for the transformer."   I explain again....... so he says he will make it right, but will have to run another wire to get power outside.

I examined the outside junction box.  The "switch leg" is wired black - black, white - white, & ground - ground with all 3 branches going to the 9 locations.  He really (apparently) thought is was a transformer.

Attach is the "as-wired" and my proposal to him to resolve the problem without running an additional hot wire out side.
His reply, "No that will not work sir. You will not have neutral outside. And you don't have a actual switch leg coming back. You have the neutral wire returning. If outside switch was only switch then it would work but not coming back to your relay."
I added the red note and replied, "See the note in red.  There is a neutral.  It feeds through the inside switch."
He replies, "Still got to have another wire going out. It's not a problem, I can fix tomorrow."
My reply, "Don't need another wire, we can use the one switch leg for power and switch."
His reply, "Ok then which one is your return switch leg?"
I reply, "The inside switch (timer relay) is breaking into the neutral wire of the power feed going outside.  It will kill power going to the junction box."

I know I'm right, but he's the professional.  Am I losing my mind?

Thanks





« Last Edit: June 04, 2019, 10:40:35 am by David Allred »
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John Roberts {JR}

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Re: Tell me I'm not losing my mind
« Reply #1 on: June 04, 2019, 10:57:17 am »

I had a similar question until I went back and reread your post. Your schematic is not obvious that the timer switch is externally powered (via USB). Your current version section seems unfinished or incorrect, but presumably that is working.

It is probably not good practice (code?) to break the neutral instead of line. This leaves the hot leg energized even when neutral is open. 

JR
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David Allred

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Re: Tell me I'm not losing my mind
« Reply #2 on: June 04, 2019, 11:22:46 am »

I had a similar question until I went back and reread your post. Your schematic is not obvious that the timer switch is externally powered (via USB). Your current version section seems unfinished or incorrect, but presumably that is working.

It is probably not good practice (code?) to break the neutral instead of line. This leaves the hot leg energized even when neutral is open. 

JR
The illustration was made after the wiring was complete to show him how I thought it could be made to work.  The "Current" definitely does NOT work, as the hot leg from the breaker box is not connected to anything.
You raise a similar concern as the electrician about breaking the neutral.  He said the light might not work right.   I will change the relay to the hot leg.
« Last Edit: June 04, 2019, 11:33:13 am by David Allred »
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David Allred

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Re: Tell me I'm not losing my mind
« Reply #3 on: June 04, 2019, 11:41:51 am »

When I was a teenager doing construction work the general contractor taught me to wire switches on the neutral.  His logic (that still seems logical) was that IF the circuit was still live and you grabbed the neutral wire in the switch box and touched the grounded box you wouldn't get shocked.  I have held that principle for 30+ years.  On a given circuit there would be fewer shock hazards.
I learned something new today.
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Tim McCulloch

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Re: Tell me I'm not losing my mind
« Reply #4 on: June 04, 2019, 12:01:01 pm »

When I was a teenager doing construction work the general contractor taught me to wire switches on the neutral.  His logic (that still seems logical) was that IF the circuit was still live and you grabbed the neutral wire in the switch box and touched the grounded box you wouldn't get shocked.  I have held that principle for 30+ years.  On a given circuit there would be fewer shock hazards.
I learned something new today.

It's a Code violation to open the neutral without simultaneously opening the line.  With a single pole switch the LINE, and only the line, is to be switched.
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Chris Hindle

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Re: Tell me I'm not losing my mind
« Reply #5 on: June 04, 2019, 12:30:29 pm »

When I was a teenager doing construction work the general contractor taught me to wire switches on the neutral.  His logic (that still seems logical) was that IF the circuit was still live and you grabbed the neutral wire in the switch box and touched the grounded box you wouldn't get shocked.  I have held that principle for 30+ years.  On a given circuit there would be fewer shock hazards.
I learned something new today.
Wow.
Just wow.
With the line live throughout the "network", how is there less shock risk?
Pretty spectacular shock risk just changing a light bulb...
Ever have one where the bulb breaks off, and you go in with needle-nose to clear the socket?
My dad taught me to keep one hand in my pocket when digging around a panel. That's saved my ass a few times....
Chris.
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Stephen Swaffer

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Re: Tell me I'm not losing my mind
« Reply #6 on: June 04, 2019, 12:55:30 pm »

When I was a teenager doing construction work the general contractor taught me to wire switches on the neutral.  His logic (that still seems logical) was that IF the circuit was still live and you grabbed the neutral wire in the switch box and touched the grounded box you wouldn't get shocked.  I have held that principle for 30+ years.  On a given circuit there would be fewer shock hazards.

Until someone turns a light "off" and proceeds to replace the fixture??

Tim is right-specific reference is 404.2.  Following standard practice will result in less confusion.  Unfortunately, a signficant number of electricians don't understand how to make a circuit work they just know to connect the hot wire to the brass colored screw and so on....and please don't confuse them by asking them to explain a 3 way switch!

Neutral switching used to be common practice-you'll still run into in older homes quite frequently.
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Steve Swaffer

David Allred

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Re: Tell me I'm not losing my mind
« Reply #7 on: June 04, 2019, 04:21:31 pm »

Wow.
Just wow.
With the line live throughout the "network", how is there less shock risk?
2 rooms on a circuit.  4 plugs each and 1 switch each. 
Neutral switches - 8 shock points.
Hot switches - 10 shock points.
See? There is logic to that singular point. 
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Mike Sokol

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Re: Tell me I'm not losing my mind
« Reply #8 on: June 04, 2019, 04:50:14 pm »

It's a Code violation to open the neutral without simultaneously opening the line.  With a single pole switch the LINE, and only the line, is to be switched.

Opening just the neutral, either through a switch or a fuse, is a very bad idea. I remember snooping around the Maryland Theater back in the 70's when they still had their original 1920's wiring in place, and every single stage lighting fixture had two fuses. One fuse on the hot and one fuse on the neutral. The electrician I was working with at the time told me the original designers wanted to protect the neutral wires until everyone figured out how dangerous backfeeding the voltage/current through the tungsten bulb would be.                                                                                                     
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brian maddox

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Re: Tell me I'm not losing my mind
« Reply #9 on: June 04, 2019, 10:14:06 pm »


Neutral switching used to be common practice-you'll still run into in older homes quite frequently.

Yup.  Found out my house has a few of those the hard way.  Got bit because i just turned the switch off rather than killing the breaker before digging into something [i forget what exactly].  I had never even HEARD of neutral switching before....
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Re: Tell me I'm not losing my mind
« Reply #9 on: June 04, 2019, 10:14:06 pm »


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