Electrician Talk banner
1 - 20 of 39 Posts

·
Registered
Joined
·
364 Posts
Discussion Starter · #1 · (Edited)
Can anyone offer any specific techniques and tips for troubleshooting? I realize this is a difficult question because the ability to troubleshoot comes with experience and time, but when I learned the "divide and conquer" technique here (repeatedly splitting the circuit in half to pinpoint problems), it was really useful. Are there any others like that? Currently, I am doing mostly residential, along with some light commercial. Troubleshooting tips specific to resi would be really helpful. I'm wondering if there's some kind of protocol or checklist that you can use I troubleshoot. Thanks in advance.
 

·
Questioner of Authority
Joined
·
880 Posts
Don't trust homeowners to know what they are talking about. "This just stopped working" means very little. Men are especially untrustworthy about household issues with their ego getting in the way of their admission of guilt. Best bet, keep the man of the house out of the house.

Knock the obvious out first. Look for signs of recent visits by Plumbers, sheetrockers, hackass rival electricians, cable or installers, signs of anybody digging in the yard, new electrical parts like receps and switches or harry homeowner getting ballsy with a new tool/toy. Ask if anybody has been messing about with remodeling in the house.

Unplug everything on a recep circuit, if that is what you are looking at.

Don't trust panel labeling. Don't trust a glow pen, there is a reason why it is called an "idiot stick". Trust your meter, except when you can't (know how it works).

If the issue is not obvious work common problems. Poor splicing and terminations are often factor 1 in many troubleshooting scenarios. Pinched wiring in lighting fixtures. Switched receps homeowners didn't know they had.

Try and figure out where things are being fed from and use that knowledge as a map.

Draw things out, it often is obvious if you sketch down how you think something is wired.

Work one step at a time. Test. Move on to next possible solution.

Unplug computers, tvs, stereos and other expensive products. You don't know what dumbass could have been around before you. Being unaware of MWBCs and messing with neutrals could turn expensive things into smoke.
 

·
corn-fused
Joined
·
4,769 Posts
Don't trust homeowners to know what they are talking about. "This just stopped working" means very little. Men are especially untrustworthy about household issues with their ego getting in the way of their admission of guilt. Best bet, keep the man of the house out of the house.

Knock the obvious out first. Look for signs of recent visits by Plumbers, sheetrockers, hackass rival electricians, cable or installers, signs of anybody digging in the yard, new electrical parts like receps and switches or harry homeowner getting ballsy with a new tool/toy. Ask if anybody has been messing about with remodeling in the house.

Unplug everything on a recep circuit, if that is what you are looking at.

Don't trust panel labeling. Don't trust a glow pen, there is a reason why it is called an "idiot stick". Trust your meter, except when you can't (know how it works).

If the issue is not obvious work common problems. Poor splicing and terminations are often factor 1 in many troubleshooting scenarios. Pinched wiring in lighting fixtures. Switched receps homeowners didn't know they had.

Try and figure out where things are being fed from and use that knowledge as a map.

Draw things out, it often is obvious if you sketch down how you think something is wired.

Work one step at a time. Test. Move on to next possible solution.

Unplug computers, tvs, stereos and other expensive products. You don't know what dumbass could have been around before you. Being unaware of MWBCs and messing with neutrals could turn expensive things into smoke.
very good ! i commend you:thumbup:
 

·
Registered
Joined
·
12,167 Posts
Hawk did a good job listing stuff.

I'd like to add that although you can't trust what the homeowner says, it is good to listen carefully and ask them questions. Try to understand what they are saying.

It would also be good to notice if TV and such are working or not. Before you start to work on anything, it would not be a bad idea to ask the homeowner to turn on the TV (so you can see it works), then do like Hawk said and unplug it.

It sometimes can help if you plug an extension cord into a known good outlet and bring it to where you are having problems to determine if you are missing a hot or neutral.

Just because an outlet is working, doesn't mean it is not the problem.

Troubleshooting is a thinking mans game. Slow down and think about what you see.
 

·
corn-fused
Joined
·
4,769 Posts
and ask the ho if ANYTHING has been done just before this problem ocurred. often it will be something they didnt think could even affect the electricity, such as hanging cabinets in the garage, where a screw went through the wire!:whistling2:
 

·
Registered
Joined
·
364 Posts
Discussion Starter · #8 ·
hardworkingstiff said:
Hawk did a good job listing stuff. I'd like to add that although you can't trust what the homeowner says, it is good to listen carefully and ask them questions. Try to understand what they are saying. It would also be good to notice if TV and such are working or not. Before you start to work on anything, it would not be a bad idea to ask the homeowner to turn on the TV (so you can see it works), then do like Hawk said and unplug it. It sometimes can help if you plug an extension cord into a known good outlet and bring it to where you are having problems to determine if you are missing a hot or neutral. Just because an outlet is working, doesn't mean it is not the problem. Troubleshooting is a thinking mans game. Slow down and think about what you see.
Why the TV in particular?

I like the extension cord idea. You mean test the hots against each other, and test the neutrals against each other to see if you are getting 0V (or 120 for hots on opposite legs)?
 

·
Registered
Joined
·
364 Posts
Discussion Starter · #9 ·
hardworkingstiff said:
Just because an outlet is working, doesn't mean it is not the problem.
How could you tell if that recep is still the problem? Voltage test?
 

·
Registered
Joined
·
12,167 Posts
How could you tell if that recep is still the problem? Voltage test?
Pull it out and inspect it and make sure the voltage is actually leaving. I only saw this happen twice in my life, but I don't do a lot of trouble shooting either.
 

·
I like ceiling fans & EMT
Former commercial, occasional (small) residential
Joined
·
1,320 Posts
After disconnecting power, I rigged a male plug to clamp to each lead of my meter. So I could plug one end into one outlet, another into another, as far apart as I liked if I used extension cords. After checking again for AC, I set my meter to the transistor test setting so it would beep at ~0 ohms. Found an open hot in a wall this way (it was cut through some time in the past).
 

·
Registered
Joined
·
364 Posts
Discussion Starter · #12 ·
dspiffy said:
After disconnecting power, I rigged a male plug to clamp to each lead of my meter. So I could plug one end into one outlet, another into another, as far apart as I liked if I used extension cords. After checking again for AC, I set my meter to the transistor test setting so it would beep at ~0 ohms. Found an open hot in a wall this way (it was cut through some time in the past).
Transistor test? You mean diode test?
 

·
I like ceiling fans & EMT
Former commercial, occasional (small) residential
Joined
·
1,320 Posts
Transistor test? You mean diode test?
Yep. Diodes and transistors can be tested exactly the same way, and I have had to replace hundreds more transistors than diodes, so I forget the symbol on most meters corresponding to this setting is actually a diode.
 

·
Conservitum Americum
Joined
·
8,963 Posts
The number one thing to find out is exactly what the problem is and when it occurs. That is easier said than done because it is almost never what the customer says. Also, educate your customer as to the proper operation of the equipment.

Carry two meters and periodically test the meter and leads for intermittent opens especially when you get erratic readings. An analog meter always comes in handy when the problem reading is fast and intermittent.

I carry a few high wattage resistors for small loads and checking cumulative resistance readings on long runs.

Always ask when the problem started and what happened, who was around right before that. I cannot tell you how many times that has helped with the diagnosis. At least it gives you an area to start looking in.

In my world, I find power (amperage) and power supplies are at fault about 80 percent of the time.



I just got through with a serial numbered device install on a polling loop (5 loops) that another company did and couldn't get to work. I can almost say I encountered everything that could have gone wrong on this project. The devices contain a small chip and have assigned serial numbers. They are also directional and polarity sensitive. Of course 54 devices on 5 loops, three floors and people everywhere walking in front of motions, opening doors and windows you just closed...

I found devices wired to devices, devices to reversed SIMS, wrong value resistors, no resistors, polling loops cut, polling loops to polling loops, positive to negative, some devices were broken, and the last one, which was the only hardwired zone, was wired red and green at the door contact then red and yellow at the panel. SHEESH!

This took me, and others occasionally, about 25 days to wring out.
 
  • Like
Reactions: jeffmoss26

·
Donuts > Fried Eggs
Joined
·
17,042 Posts
Lots of good stuff here. To add to "work one step at a time": Only change what is necessary to troubleshoot that step, and don't change anything else until you've completed each step. Everything that gets changed is one more variable that has to be eliminated as the cause:

If you're testing a light and it starts working after you hit 11 switches, well that's now 11 switches you have to check one-at-a-time to see which was actually the culprit.

Also: Success is not a sign to stop troubleshooting. If you can't explain exactly what you found and why it caused the problem, then there's a good chance you haven't found the cause. Just because the light starts working again don't mean it's actually fixed.
 

·
Registered
Joined
·
32,120 Posts
Don't trust homeowners to know what they are talking about. "This just stopped working" means very little. Men are especially untrustworthy about household issues with their ego getting in the way of their admission of guilt. Best bet, keep the man of the house out of the house.

.
Listen to the customer for about a minute but do not trust any thing they say be it residential, commercial or industrial. Anything longer than a minute they are wasting your time with useless, incorrect information.
 

·
Registered
Joined
·
12,167 Posts
Why the TV in particular?

I like the extension cord idea. You mean test the hots against each other, and test the neutrals against each other to see if you are getting 0V (or 120 for hots on opposite legs)?
TV because it's usually the most expensive electronic equipment in the house (and unplug computers too). The reason I think you should unplug them is if they are part of a MWBC and you move some wires that have a loose neutral connection, you could damage the electronics. It's just a CYA move.

As far as the extension cord, it gives you a known H,N,G and you can test w/out wondering if you have power or not. You can test H to H or H to N or N to N or N to H. It's not the 1st thing I would do, but if you are in a device and you're not sure what you have (voltage wise), having the extension cord there helps.
 
  • Like
Reactions: sparky970

·
Senile Member
I make all the electrons line up for their Flu shots
Joined
·
33,816 Posts
The protocol for trouble shooting according to OSHA is to turn off all power, lock out, tag out, put on a space bubble suit, and then go write a report.
 

·
Questioner of Authority
Joined
·
880 Posts
Something else I was thinking about today, on a roof un:censored:ing a RTU in the cold.
In troubleshooting, knowing THEORY is more important than knowing code. Understanding how electrical energy is transferred and utilized in different equipment is very important. Theory helps you understand what the problem is "Only half my lights work until I turn on my stove".
In construction, Code seems to be the more important facet of our knowledge. Theory to me, is more fun. Pay attention in class and ask questions. The more you know, the more fun it can be to figure something out.
 
1 - 20 of 39 Posts
Top