Solve This Service Call

Status
Not open for further replies.

480sparky

Senior Member
Location
Iowegia
We haven't had one for a while, so here's one from this morning:

Customer called yesterday. Doctor's office waiting room. Breaker "tosses sparks and won't stay on". I arrive and find a breaker turned off (marked "Waiting Room"... whooda thunk it?), and the following floor plan. The panel is in the basement at the rear of the building. STSCMap.jpg


To answer the inevitable questions:
Yes, I found the problem.
Yes, I solved the problem.
I didn't use any high-$ tools.... just what I have in my tool tote. Screwdrivers, linesmans, strippers etc.

The purpose here is to teach the art and the technique of troubleshooting. While this may seem old hat to veterans, keep in mind there's cubbies here as well.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
You're not giving us much to go on. From just the info in the drawing, my guess is:

Double-duplex receptacle #4 mis-wired, or short between adjacent terminals.
 
D

Dell3c

Guest
You've gone to the trouble of detailing the waiting room, so obviously where you encountered the solution..
So.. I'm going to eliminate the load center by saying "pitted bus" ?
 

480sparky

Senior Member
Location
Iowegia
Not near enough info given!

What.... you expect me to solve the issue over the phone? The exercise is: TROUBLESHOOT.

So, what was plugged into those outlets?

When I arrived: Nothing.

Well, maybe we have the same info that the OP was given over the phone, but we weren't there to actually see it. Without more info, I don't see how we can do anything but make guesses!

Isn't that what TROUBLESHOOTING is? Making logical conclusion based on information provided?

This is really simple: You start with the same information I did. You then investigate... gather MORE information. Try one thing, then another, and draw a conclusion from this.

Jeez: If I gave you ALL the information needed to solve the problem, there's not point to the post.

This is TROUBLESHOOTING, not guessing.

You've gone to the trouble of detailing the waiting room, so obviously where you encountered the solution..
So.. I'm going to eliminate the load center by saying "pitted bus" ?

Mistake No. 1: Assuming.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Troubleshooting tip for a short: a high-watt incandescent bulb in series with the wire at the breaker.

While a helper with a phone or 2-way radio watches the bulb for flicker, you wiggle the receptacles.

If you're alone and can't see the light, wire in a receptacle and run a cord where you can see a lamp.

Or, plug in something you can hear. I once used a shop vac as an audio indicator when I was alone.

Or, use
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
I think I would inspect the breaker first to eliminate anything funny there, if only because of the 'throwing sparks comment'. If nothing visually alarming about the breaker, take the wire off and test the hot to ground to see if I have a clear short. Determine that the breaker is supposed to be tripping. Easier than guessing which outlet to start with, and if I find the problem in the panel I can stop guessing which end of the building I'm supposed to be in. Also maybe get some info if it's an MWBC before I start opening outlet boxes.
 

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Electrician
What.... you expect me to solve the issue over the phone? The exercise is: TROUBLESHOOT.



When I arrived: Nothing.



Isn't that what TROUBLESHOOTING is? Making logical conclusion based on information provided?

This is really simple: You start with the same information I did. You then investigate... gather MORE information. Try one thing, then another, and draw a conclusion from this.

Jeez: If I gave you ALL the information needed to solve the problem, there's not point to the post.

This is TROUBLESHOOTING, not guessing.



Mistake No. 1: Assuming.
You failed to mention if the breaker was actually tripped or just off. No one said anything about solving it over the phone, you were there, we were not. Still not enough info.
 

grich

Senior Member
Location
MP89.5, Mason City Subdivision
Occupation
Broadcast Engineer
Not knowing anything else, I'd inspect all six receptacles looking for the obvious. If nothing obvious, and hoping the circuit is looping through each box, I'd break the circuit in the middle, probably at #4, and see if the breaker holds. Whether the breaker holds or not tells me which half the fault is in.

I could break the circuit at the first receptacle and work it from there, but if the fault were at the end, it would be a lot of unnecessary work to isolate it.
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
I took "cubbies" to mean cubicles.

Disconnect black from breaker. Check breaker. Remove neutral from bus, check with volt meter from black to ground and neutral. With ohm meter check from black to neutral and black to ground. Those tests should reveal a bad breaker, a short or a backfeed.

Now remove the middle receptacle, disconnect the wiring in the box and check back at the panel for what you found the first time. If still there, remove the rest and see if you can determine how the wiring and home run was run. Check each run for what you found the first time.

One of these tests should have revealed the problem.

-Hal
 

romex jockey

Senior Member
Location
Vermont
Occupation
electrician
something went to ground, so it's simply a matter of opening up devices , and which end of the circuit to start to start working from

~RJ~
 
Status
Not open for further replies.
Top