Changing switches and receptacles

[gadfly56]

You must be a younger guy if you over 40ish this is the way we were taught one finger on ground next one to the "hot" wire. To be honest it isn't a good practice because now sometimes I can't feel it and have to wet my finger

Dude, I used to work with explosives, and you're scaring me. :happysad:

 

[infinity]

I would leave the main on, plug in my favorite tool (my radio) crank it to eleven . Go hit the breakers until the radio went off. Relocate the radio to a live circuit. Change the outlets on the "off" circuit but test each ones with my fingers (to lazy to carry extra tools.) Do you guys still test with your fingers?

Back when I started, finger testing was a pretty standard practice. The old calloused sparkies would need a lick or two to get any type of tingle. We would test for blown fuses by touching the neutral bar with one hand and touching each fuse with the other hand to find the blown one.:slaphead:

 

[andyselec@aol.com]

I started doing this when I was 14 and back then I admit it hurt a little bit so I used a wiggie the first 4-5 yrs then started using my fingers more. I have even had 3 GC try it. I had a volcon fail on me once and got a nice surprise when I got hit thinking all the wires where dead now if I use a meter I also will double check with my fingers

 

[spark master]

I call BS. The worst shock I ever got was across my pinky to my thumb. My hand hurt for 2 WEEKS. I wasn't paying attention, as someone called my name, and another guy dropped a tool. I looked away, but my hand was still working until a wire nut came off. I mean serious pain for 2 weeks.

 

[ActionDave]

I call BS.....

Call it what you want. Sticking your finger and thumb on a live circuit to check for power, or using the back of your hand, was SOP for a lot of crusty, old electricians.

The one that I knew said, "Make sure and put your other hand in your back pocket."

 

[fmtjfw]

Thanks

Thanks

I have used the results of this survey as part of the argument for labeling receptacles in other than Data Processing areas that are fed with UPSs. The survey indicated that about 24% of experienced electricians would not expect receptacles in a house with the main power off to be energized.

ADDED TEXT

100 I Fixed Wiring. Conductors, raceways, etc. installed under Chapter 3 methods.

110.27 Uninterrupted Power Supply (UPS) Connected to Fixed Wiring.
(A) Labeling.
(1) When a UPS supplies fixed wiring, each place the UPS supplied circuit(s) is accessible shall have a clearly legible marking in letters not less than 6 mm (? in.) high reading ?UPS Supplied?. The label shall comply with 110.21(B).
(2) When a control panel contains a UPS which supplies current to fixed wiring external to the control panel, the control panel shall have a clearly legible sign in letters not less than 6 mm (? in.) high reading ?Caution this panel contains a UPS?. The sign shall comply with 110.21(B).
(B) Disconnecting Means. A disconnect meeting the requirements of 110.25 shall be installed for all output circuits from the UPS.
Exception: The requirements 110.27 do not apply to areas meeting all the requirements of 645 Information Technology Equipment or 646 Modular Data Centers.

SUBSTANTIATION

90.1(A) Practical Safeguarding. The purpose of this Code is the practical safeguarding of persons and property from hazards arising from the use of electricity.

The recent introduction of fixed wiring in buildings fed from UPSs in other than Information Technology Equipment areas has introduced a new hazard. Until recently when you opened the main service disconnect for a building you would be able to assume that fixed wiring was no longer energized. APC and other manufacturers are selling UPS accessories for their products to facilitate connection to fixed wiring. (For example see http://www.apcmedia.com/salestools/A...8L95_R0_EN.pdf). This installation guide does not require an output disconnect.

The recent introduction of UPSs embedded in control panels which feed external fixed wiring presents a similar hazard. I have directly experienced a case of this sort. I was tasked to replace a shunt-trip 3-pole circuit breaker with trip alarm contacts. I opened all the circuits serving the control cabinet. I measured the voltages on the circuit breaker power connections, the shunt-trip, and the trip alarm contacts. I found that the shunt-trip circuit was de-energized, but that the trip alarm contact was still energized. I opened the control cabinet (not something I normally would do, because the cabinet and associated equipment were maintained under contract by a third-party). I found that a standalone style UPS like one might buy in a big box store was inside and its output was energizing the trip alarm contacts. I also confirmed that all external power to the control panel was indeed turned off.

I am proposing the addition of 110.27 and the associated 100 I Fixed Wiring additions to the NEC to warn electricians of these new hazards. I am suggesting the use of ?UPS supplied? as labeling for receptacle outlet covers (and other covers) because it also serves as useful label for non-electrician users.

The exception is proposed because those qualified personnel working in 645/646 areas are already expecting UPS supplied receptacles.
Basis for 100 Fixed Wiring
Terms akin to Fixed Wiring are used in:
220.14(H) Fixed Multioutlet Assemblies.
250.34(C)(3)<info note> Fixed wiring systems
393.6(B)(4) fixed wiring methods
400.8(1) fixed wiring method
411.3(B)(5) fixed wiring method
500.8(B)<info note> fixed wiring
501.140(A)(2) fixed wiring methods
505.17(A) fixed wiring methods
511.7(A)(1) fixed wiring
511.16(B)(2) fixed wiring system
513.7(A) fixed wiring
513.10(C)(1) fixed wiring
513.10(D)(1) fixed wiring
513.16(B)(2) fixed wiring system
515.7(A) fixed wiring
516.7(A) fixed wiring
517.61(A)(3) fixed wiring
518.4(A) fixed wiring methods
518.4(A)<except> fixed wiring methods
520.5(A) fixed wiring method
520.5(A)<except> fixed wiring methods
530.31 fixed wiring
550.19(A) fixed-type wiring methods
550.32(D) fixed wiring method
620.21(A)(2)(b) fixed wiring
Basis for UPS labeling
I posted a poll on forums.mikeholt.com/showthread.php?t=148012 which asked in essence ?would you check for voltage at receptacles and switches after turning off and locking the service main??. There were 26 responses to the poll, 5 said they would NOT check, basically 24%. Three who chose a testing method said they would not turn off main for various reasons. The poll was posted in the Safety forum to bias the answers towards testing.
Changing switches and receptacles
Let's assume you've got a job that consists of changing the receptacles, switches, and cover plates throughout a house from ivory to almond. You ask why and the guy who hired you said it is a directive from "She Who Must Be Obeyed". They are going away for the week. So you show up and decide the simplest way to do this is to put on a head lamp and turn off the main breaker. You turn it off and padlock it.
View Poll Results: Now when you go to each box, what do you do?
Voters 21. This poll is closed

test for voltage with a non-contact voltage stick 6 28.57%
test using a wiggly 5 23.81%
test using a Digital Volt Meter 5 23.81%
test using a shorting plug (for receptacles) 0 0%
test? are you crazy, the power is off! 5 23.81%

The response from CMP-1 limited itself to the original example (an elevator control panel, and not to the general cases supplied above).

Panel Statement: The problem identified by the submitter relates to product
design and marking rather than installation. In addition, the submitter is
proposing specific requirements in the general section of the code which may
be more appropriate in other sections of the code. In sections such as
620.52(B), the submitter?s concerns are addressed.

 

[renosteinke]

I'm going to cry 'foul,' and you are honor bound to include my comments here with your proposal.

You're misapplying a poll with a misleading question. The results would have been far different had the issue of secondaty power been brought up.

No, you posted a question that -since no other details were provided - was understood to refer to routine operations on 'normal' outlets.

You are also ignoring some basic design principles, if not actual code requirements. I can't speak for others, but the UPS systems I've installed all fed panels - so shutting off the breaker would isolate the circuit from every power source. Just like you would do with a generator, or solar panels, or any other secondary supply.

 

[fmtjfw]

I'm going to cry 'foul,' and you are honor bound to include my comments here with your proposal.

You're misapplying a poll with a misleading question. The results would have been far different had the issue of secondaty power been brought up.

No, you posted a question that -since no other details were provided - was understood to refer to routine operations on 'normal' outlets.

You are also ignoring some basic design principles, if not actual code requirements. I can't speak for others, but the UPS systems I've installed all fed panels - so shutting off the breaker would isolate the circuit from every power source. Just like you would do with a generator, or solar panels, or any other secondary supply.

I apologize for posing a trick question. :ashamed: The point of the poll was to elicit what an electrician would do going into a house after turning off the main -- namely would they test each device? I was trying to gauge the hazard to electricians who don't know or are not told about a UPS feeding fixed wiring in the building.

I meant in no way to reflect on the skills or habits of anyone. The caution you described in your reply reflects well on your safety procedures.

Had I asked, if you go into a house with the main disconnected but contains a UPS system that energized receptacles, then I would not have gathered information I sought.

How would you have done it?

I am trying to get warnings of hazardous conditions caused by the introduction of UPSs to fixed wiring. The first attempt was not accepted. I'm trying to get more protection for "us".

 

[PetrosA]

I apologize for posing a trick question. :ashamed: The point of the poll was to elicit what an electrician would do going into a house after turning off the main -- namely would they test each device? I was trying to gauge the hazard to electricians who don't know or are not told about a UPS feeding fixed wiring in the building.

I meant in no way to reflect on the skills or habits of anyone. The caution you described in your reply reflects well on your safety procedures.

Had I asked, if you go into a house with the main disconnected but contains a UPS system that energized receptacles, then I would not have gathered information I sought.

How would you have done it?

I am trying to get warnings of hazardous conditions caused by the introduction of UPSs to fixed wiring. The first attempt was not accepted. I'm trying to get more protection for "us".

Personally, I would rather see a mandatory LED indicator light on receptacles that are UPS fed. I've never run across hardwired UPS fed circuits in residential, so I would definitely not be on the lookout (usually you'd hear a UPS as soon as the power is cut off in residential). A label would most likely be applied to the plate, and that could get changed or the label could get worn or lost. A requirement to use indicating receptacles would do better at warning everybody, not only electricians.

 

[renosteinke]

Doesn't the NEC already require that when devices or panels are fed from more than one power source, that they be so labled?

I'm still having trouble imaginging any sort of UPS where there is not a transfer switch involved, somewhere. I can see where it might not be obvious at the disconnect to one source of supply - but I would hope the transfer switch ought to be obvious.

I've never seen a UPS that fed directly into the power network with anything as simple as back-feeding a breaker. Such an arrangement would seem to put PoCo personnel at risk.

Then again, there are those solar panels with 'micro-inverters.' Those backfeed an ordinary breaker into the panel, and are supposed to shut down automatically where there is no utility power.

It's not a bad concern, though - as the same situation can arise with every secondary form of power.

Now, if our concern is based upon un-listed DIY arrangements .... all bets are off.

 

[fmtjfw]

Here are a couple possibilities:

1) Home theater, someone's spent $$K on the stuff and adds a UPS for $500 -- $1000. All the A/V & computer cabling is installed as fixed wiring and he has the UPS connected into fixed wiring as well. Branch circuit feeds UPS and UPS feeds receptacles.

2) Computer nut or work-at-home computer professional has UPS wired in for his at home computer room/ office.

See the comment for a link to adapter kits to change plugin UPSs to fixed wiring, changing the backplate from cords and receptacles to knockouts.

Here is an example of someone's installation:

http://www.diychatroom.com/f18/safest-way-put-ups-inline-circuit-88927/

 

[K8MHZ]

Back when I started, finger testing was a pretty standard practice. The old calloused sparkies would need a lick or two to get any type of tingle. We would test for blown fuses by touching the neutral bar with one hand and touching each fuse with the other hand to find the blown one.:slaphead:

Yep. That practice was 'by the book' many years ago. Check this out. I think I got it from 480sparky.

 

[Dennis Alwon]

You must be a younger guy if you over 40ish this is the way we were taught one finger on ground next one to the "hot" wire. To be honest it isn't a good practice because now sometimes I can't feel it and have to wet my finger

I have tested with my fingers for years but only when I am too lazy to get the meter.

 

[K8MHZ]

Here are a couple possibilities:

1) Home theater, someone's spent $$K on the stuff and adds a UPS for $500 -- $1000. All the A/V & computer cabling is installed as fixed wiring and he has the UPS connected into fixed wiring as well. Branch circuit feeds UPS and UPS feeds receptacles.

2) Computer nut or work-at-home computer professional has UPS wired in for his at home computer room/ office.

See the comment for a link to adapter kits to change plugin UPSs to fixed wiring, changing the backplate from cords and receptacles to knockouts.

Here is an example of someone's installation:

http://www.diychatroom.com/f18/safest-way-put-ups-inline-circuit-88927/

I am thinking about putting my UPS in the basement just below the wall where the receptacles it feeds are. The UPS batteries weigh 102 lbs each and I rotate them from use to storage.

Having the UPS and battery downstairs would free up a bunch of space.

The affected receptacles would be permanently marked to indicate a back up power source.

 

[K8MHZ]

I have tested with my fingers for years but only when I am too lazy to get the meter.

Meter or not, I still do it as a final check before I begin the operation.

Just curious.....how do you (as in all of you) check for an energized hot wire in a single switch box, not grounded, with no neutral?

 

[Dennis Alwon]

Meter or not, I still do it as a final check before I begin the operation.

Just curious.....how do you (as in all of you) check for an energized hot wire in a single switch box, not grounded, with no neutral?

Generally I don't worry about it if I am not near a ground and the cable has no ground. Tape off the wire and change the box or if I am changing a device I do it live. You certainly can make an extension to a ground somewhere if you wanted to.

BTW- I don't really want to encourage this. I grew up doing it in NY and no matter how careful you try and be- it happens....I do generally turn off the circuits and my men almost always do. One thing for the dumb boss to do it but not my men.

 

[K8MHZ]

Generally I don't worry about it if I am not near a ground and the cable has no ground. Tape off the wire and change the box or if I am changing a device I do it live. You certainly can make an extension to a ground somewhere if you wanted to.

BTW- I don't really want to encourage this. I grew up doing it in NY and no matter how careful you try and be- it happens....I do generally turn off the circuits and my men almost always do. One thing for the dumb boss to do it but not my men.

Have you tried using a tick tracer?

If so, how accurate?

I have found that all tick tracers are not alike. I have one that works very well and several that are questionable at best.

I don't encourage live work either, but I do it every now and then. Old school, I guess.

 

[Dennis Alwon]

The tick tracer can give a false positive which is the good in a way. It may pick up transient voltages from cables next to the one you are testing. They also can be finicky and I don't trust them. I will use them and then double check with my fingers but again the meter is the best way.

 

[K8MHZ]

The tick tracer can give a false positive which is the good in a way. It may pick up transient voltages from cables next to the one you are testing. They also can be finicky and I don't trust them. I will use them and then double check with my fingers but again the meter is the best way.

I am going to have to not agree. The meter only tests that which the leads are connected to. The tick tracer doesn't have to be connected.

Like, for poking around in an old over stuffed box, a tick tracer is the way to go. They do require some finesse and getting used to, but a meter won't find a hidden hot wire that can nail you when you commence to poking around inside.

Every tool has it's good and bad points. A meter may be the best choice for some applications, but a good non-contact tester is the best choice in others. Redunancy, using both, is better yet, of course.

 

[K8MHZ]

I think my favorite combo is first, my trusty Greenlee tick tracer, followed by my Vol-Con XLII solenoid tester. Then fingers.

I seldom use a DVOM unless I am looking for precision. They can give false readings, too.

The Vol-Con that I have is great. No controls. It goes from voltage to continuity all by it's self, indicates (roughly) voltage and shows DC or AC with only a glance needed. It also has both motion and sound indicators. Great troubleshooting tool. The only way it could get better would be to have a pop up tick tracer built in.