View Full Version : Reversed polarity Outlets
Sam Morris
03-03-2010, 07:49 PM
I would like to get everyone opinion on a house built around 1980 that had most all the outlets in the house hot neutral reversed. Did the electrician mess up or was this a common practice for this time period. How would everyone rate this, defective or marginal. Your thoughts please. Thanks
Jerry Peck
03-03-2010, 08:05 PM
I would like to get everyone opinion on a house built around 1980 that had most all the outlets in the house hot neutral reversed. Did the electrician mess up or was this a common practice for this time period. How would everyone rate this, defective or marginal. Your thoughts please. Thanks
Big time screw up.
Always defective.
Never acceptable.
Jim Port
03-03-2010, 08:06 PM
Not an inspector so i won't comment on defect etc.
There is no reason for a 30 year old installation to have reverse polarity. Proper installation procedures were well spelled out and should have been followed.
H.G. Watson, Sr.
03-03-2010, 08:30 PM
Sam Morris,
You've made a few topic posts in the past flying by, but don't seem to be able to find them (or RETURN) to them and provide follow-up to those who respond to you (so with repeat topics one wonders if you ever read the responses you generated!).
So I'll start off by letting you know that after you log in you visit your own profile and review ALL of your prior posts and re-visit all of the topics you started.
You can also "subscribe" to threads, set email notifications in your User CP (control panel) and be notified when posts are made including links to those "subscribed" threads (whether you created the topic thread or not).
You asked a similar question several months ago regarding a 1960s home. Amongst the responses to that question were included bits of history as to the progression of polarized receptacles, and later grounded polarized receptacles.
We'd like to think that the NEC has become progressively safer with each review and subsequent edition, not the reverse.
It would therefore not be logical that something unsafe in earlier years would later be allowed.
Here is a direct link to the aforementioned thread you started, please review the responses. If after having read it in its entirety you still have questions, post them here: I'm sure they will be responded to.
CLICKABLE LINK: http://www.inspectionnews.net/home_inspection/electrical-systems-home-inspection-commercial-inspection/14287-outlets-49-year-old-house-hot-neutral-reversed.html#post90987
I'm curious why you're asking these questions if you've been "inspecting for four years". Am I missing something?
How are you determining reverse polarity? Are you using a three-prong "outlet tester"? In a combination GFCI receptacle, or one "protected" downstream (especially in an area not required to have GFCI protection at the time of original construction!?!)? Is there a possiblity you're testing outlets on Multi-Wire-Branch-Circuits (MWBCs)?
1980s still allowed floating grounds, earlier combo gfci/receptacles did not lock-out due to wiring errors. If you truly have a reverse polarity situation it is a WIRING ERROR, was then, and is now. Was not allowed then, and isn't now: Is unsafe, and a life safety issue. If you're using a 3-prong outlet tester on a GFCI receptacle installed on a MWBC that would not be a good thing.:eek:
Sam Morris
03-03-2010, 09:09 PM
The outlets were 3 prong outlets, using a small ideal outlet tester. I was refering to outlets in the bedroom , living room , kitchen and bathroom outlets not the GFCI exterior outlets. The service panel was grounded with rod in ground and plumbing ground.
Thank you for your honesty. I so glad we can all learn something from you.
Jerry Peck
03-03-2010, 09:19 PM
If you're using a 3-prong outlet tester on a GFCI receptacle installed on a MWBC that would not be a good thing.:eek:
I'm trying to figure out what you are referring to and (not being able to figure out what you are referring to) why it is not a good thing? :confused:
Please explain.
Sam Morris
03-03-2010, 09:36 PM
I'm trying to figure out what you are referring to and (not being able to figure out what you are referring to) why it is not a good thing? :confused:
Please explain.
Checking receptacles during a home inspection using a ( Ideal SureTest branch curcuit tester. Wasnt that clear
H.G. Watson, Sr.
03-04-2010, 09:00 AM
I'm trying to figure out what you are referring to and (not being able to figure out what you are referring to) why it is not a good thing? :confused:
Please explain.
3-light testers are NOT for use on MWBCs (hot-hot-neutral-ground). Some three-light testers will indicate reverse wiring when actually 240V is present. Some 3-light testers will indicate reverse wiring when GFCI is present and actually neutral is open.
1. reverse polarity indication may not be reverse polarity but open ground. 3-light testers may have their usefullness but are not definitive for determining the correctness of wiring, or the incorrectness.
See (CLICKABLE LINK) this archieved article from EC&M (1998): Three-Lamp Circuit Tester: Valid Tester or Night-Light? (http://ecmweb.com/mag/electric_threelamp_circuit_tester/)
2. Two wire systems, older GFCIs, metal faceplates, K & T, MWBC
See (CLICKABLE LINK) this archieved article from EC&M (2000) by Mike Holt:
Replacing 2-Wire Ungrounded Receptacles (http://ecmweb.com/mag/electric_replacing_wire_ungrounded/index.html)
3. If MWBC and the GFCI receptacle is wired through (load side out not pigtailed) therefore not installed to protect only the face, is tripped (opens only the HOT), the accompanying Hot (two hots share neutral) remains closed as does the "neutral", Current from the other "side" of the circuit (hot) can backfeed on the neutral. There are a host of other possiblities depending on various wiring errors, devices plugged in and working electricity elsewhere on the MWBC, and vintage/effectiveness of the equipment that may installed. Similar issues as to why we now require single pole circuit breakers to be tied together to cause the other pole to Open when tripped for MWBCs (or a dble pole breaker) now - one of the reasons why in the 80s we were not allowed to use load side on gfci receptacles for ungrounded 2-wire systems or MWBCs - doesn't mean it wasn't done. That time was common place to "feed through" most receptacles, not "pig tail" them. I'm concerned about both MWBC and open ground here when pre-99 code cycle home, 3-light tester, latest two posts indicating bathroom has no gfci protection (required since IIRC mid 70s) apparently sharing circuit with bedrooms and hall, and "reverse polarity" "determination" by the OP, MWBCs still cost/materials savings regionally popular wiring method in 80s (TN poster) at least in TVA country.
4. IIRC floating grounds such as described in Mike Holts article above (#2) I believe were last allowed in the 99 code cycle. Using intermittant attachments to metalic water pipes was a common practice (both vintage of homes, this topic string and prior) newer plumbing materials (non-metalic) have become commonplace - may be interruption in that prior path (and one of the (many) reasons it is not allowed anymore).
5. Also, a differential current can result from other causes such as sharing the neutral with another ungrounded conductor or from capacitive leakage between the ungrounded circuit conductor and ground.
6. Since we're discussiong a 1980 home, the likelyhood of older style GFCI receptacles are likely (lacking lockout for reverse wiring, older, failing, devices, older wiring errors, older devices not well marked line & load terminals, etc.
See (CLICKABLE LINK) EC&M article (circa 1999) by Jack Wells (Pass & Seymour) here: Think like a GFCI (http://ecmweb.com/mag/electric_think_gfci/index.html)
especially:
Multiwire circuits. Multiwire circuits are sometimes used in dwellings, particularly for serving kitchens. Even more frequently, multiwire circuits are used in the wiring of hotels, dormitories, hospitals, nursing homes, and other types of buildings.
Multiwire circuits have two or more ungrounded conductors sharing a common neutral, as in a 120/240V, single-phase circuit or a 208Y/120V, 3-phase circuit.
GFCI receptacles can be used on multiwire circuits, but they must be wired such that the neutral on the load side of the GFCI is not shared by two ungrounded conductors. Failure to observe this requirement will result in a differential current any time a load served by an ungrounded conductor not connected to the GFCI is energized, immediately tripping the GFCI.
Keep in mind that a repeatedly tripped in the past older GFCI may no longer trip, AND if wired reverse, even if tripped would still power the face integral receptacle.
I think it is important to note how an open ground or a 2-wire no ground circuit can effect the safety and usefulness of using a three-light tester, add complications of a MWBC and/or a GFCI-receptacle (especially an older one) and with the inexperienced user and certain circumstances some dangerous situations may result from the use of one.
Understanding that a reverse polarity indication from such a tester can actually be caused by an open or missing ground. The quality of the question(s)and response(s) (details) from the OP including his response as to the lack of GFCI to a 1980s bathroom receptacle, how he is "testing" or determining "reverse polarity", etc. do not give me confidence, especially the similar/prior topic string I referenced in my earlier post from same OP re: reverse polarity 1960s dwelling. I have no idea the vintage of his "tester", his "testing procedures", he makes no mention of using a separate lamp, etc.
7. That same dated article (link from #6 above) outlines some additional precautions regarding testing such vintage installations under the section on testing.
GFCI testing
Since every GFCI has an integral "test button," the first and most important test is simply to push the test button after energizing the circuit. The internal test circuit performs a complete test of the functionality of the GFCI. Since each GFCI is required by UL to undergo an end-of-line calibration test to assure that the GFCI is tripping within the prescribed 4mA to 6mA trip threshold within the defined clear time, it should not be necessary to check calibration in the field.
Line-load miswiring. You can easily verify with no special test instruments that line terminations have been made properly. Simply insert a night light (or a circuit tester) into the GFCI receptacle. Push the "test button." If the GFCI trips but the night light or circuit tester stays energized, the GFCI receptacle is wired with reverse line-load connections. The GFCI needs to be removed and properly wired.
Some GFCI receptacles have an integral light that can indicate line-load reversed wiring. With this type of GFCI receptacle, you don't even need a night light; they will indicate line-load reversal when the GFCI test button is pushed.The GFCI trips but the indicator light stays illuminated, indicating that the receptacle is energized even though the GFCI tripped. Since some GFCI receptacles have indicator lights that are normally illuminated when the GFCI trips (the reverse of the type previously described), care must be taken to read and understand the instructions of the GFCI being installed.
GFCI testers. If you're from Missouri and simply don't believe the internal test circuit, then you need to exercise care in selecting the GFCI tester and in interpreting the results. It wasn't until the 1993 Edition of UL 1436, Safety Standard for Outlet Testers and Similar Devices, that the requirements for GFCI testers were coordinated with the requirements for GFCIs themselves. Testers that are not UL listed and UL-listed testers produced prior to 1993 may contain test circuits that do not properly test the GFCI. Indeed, they may indicate an unsatisfactory test when the GFCI is functioning fully in accordance with the UL GFCI standard.
Some testers not meeting UL 1436-1993 have timing circuits that limit the test current to a duration of 200 ms. If the GFCI takes more than 200 ms to trip (as permitted by UL), these testers may never trip some GFCIs that are in full compliance with UL requirements. Therefore, if you choose to use a GFCI tester, make sure it's listed to the 1993 Edition of UL 1436.
Some GFCI testers are relatively simple circuit testers with an additional test button. Others have milliammeters or dials that can be used to select various test currents. When using any of these more sophisticated testers, do not assume that it's accurately checking the calibration of the GFCI. There is very likely some capacitive leakage and possibly some harmless ground fault leakage "preloading" the GFCI. Consequently, a GFCI that is tripping within the UL time/current requirements may, according to the tester, be tripping at 3mA. In this case, the tester is simply giving a misleading reading.
Reverse polarity. Since testers establish a test circuit between hot and equipment ground, if the receptacle into which the tester is plugged is wired with reverse polarity, there will not be a voltage across the tester and test current will not flow. The GFCI will not trip and thus the GFCI might erroneously be considered defective.
Testing GFCIs on nongrounding circuits. Testers should not be used to test GFCIs installed as replacements for two-wire receptacles on nongrounding circuits. By design, GFCI testers will not test a GFCI protecting a 2-wire circuit and can expose the user to a potential shock.
The test button integral to the GFCI applies the test current between hot and neutral. This is not the case with GFCI testers; the test current in these devices is applied between hot and the equipment ground. Therefore, if there is no equipment ground, no test current will flow. If there are any exposed metal parts connected to the receptacle grounding contact (such as a metal face plate or a weatherproof cover), they will be energized by the test device. Since some of the test devices apply up to a 30mA test current; using such a tester on a 2-wire circuit while touching a metal cover plate could result in an uncomfortable shock.
Keys to testing GFCIs.
* Use the GFCI integral test button.
* Check for line-load reversal using the GFCI integral test button supplemented with a lamp or appliance.
* Be sure that any GFCI tester used is listed to the current UL standard.
* Do not use GFCI testers on two-wire nongrounding circuits.
Conclusion
The use of GFCIs, both required and otherwise, has mushroomed over the years, from just underwater swimming pool lights in 1968 to 33 references in the 1993 NEC, with even more to come. Now that GFCI installations number in the millions per year, repetitiveness can result in complacency. Not all GFCIs are alike. The installation layout needs to be evaluated and the most appropriate GFCI selected for the job, and you must adhere to all wiring instructions and markings.
Threw this together on the fly, have to head out soon, should give you an "idea" about some of what I was thinking about when I made that post to the OP and why. Will check in if Wi-fi works while I'm in between tests/etc. at the Hosp. Will likely be there most of the day, if past experience with their appointment scheduling hasn't been improved.:rolleyes:
H.G. Watson, Sr.
03-04-2010, 09:13 AM
The outlets were 3 prong outlets, using a small ideal outlet tester. I was refering to outlets in the bedroom , living room , kitchen and bathroom outlets not the GFCI exterior outlets. The service panel was grounded with rod in ground and plumbing ground.
Thank you for your honesty. I so glad we can all learn something from you.
Here is a direct link to the aforementioned thread you started, please review the responses. If after having read it in its entirety you still have questions, post them here: I'm sure they will be responded to.
CLICKABLE LINK: http://www.inspectionnews.net/home_inspection/electrical-systems-home-inspection-commercial-inspection/14287-outlets-49-year-old-house-hot-neutral-reversed.html#post90987
I'm curious why you're asking these questions if you've been "inspecting for four years". Am I missing something?
How are you determining reverse polarity? Are you using a three-prong "outlet tester"? In a combination GFCI receptacle, or one "protected" downstream (especially in an area not required to have GFCI protection at the time of original construction!?!)? Is there a possiblity you're testing outlets on Multi-Wire-Branch-Circuits (MWBCs)?
1980s still allowed floating grounds, earlier combo gfci/receptacles did not lock-out due to wiring errors. If you truly have a reverse polarity situation it is a WIRING ERROR, was then, and is now. Was not allowed then, and isn't now: Is unsafe, and a life safety issue. If you're using a 3-prong outlet tester on a GFCI receptacle installed on a MWBC that would not be a good thing.:eek:
Checking receptacles during a home inspection using a ( Ideal SureTest branch curcuit tester. Wasnt that clear
I'm trying to figure out what you are referring to and (not being able to figure out what you are referring to) why it is not a good thing? :confused:
Please explain.
Needs a separate lamp to test in addition to a 3-light tester at a minimum! Note he said Ideal "tester" not analyzer so that means to me something along the lines of an Ideal 61-500 or 61-501 IDEAL INDUSTRIES, INC. - Receptacle Testers (http://www.idealindustries.com/products/test_measurement/electrical_testers/receptable_testers.jsp) or a 61-035 or 61-051 IDEAL INDUSTRIES, INC. - E-Z CheckĀ® Circuit Testers (http://www.idealindustries.com/products/test_measurement/electrical_testers/circuit_tester_e-z_check.jsp) . Note links provide additional links to "instructions" ;) . Neither should be used on MWBC, the E-Z Check Circuit Testers state in the instructions that they may show reverse polarity on some GFCI protected receptacles when actually open neutral, etc. All four models are strictly for use with 125VAC branch circuits, the E-Z Check Testers are strictly for use with 3-wireVAC branch circuits (the third wire referring to equipment grounding conductor "wire"), They should not be used on MWBCs. All four versions of these testers indicate they should not be used unless and until all GFCI devices have been tested using their own test button, and confirming that the face and circuit has indeed been tripped, if not, not to proceed using the "tester". Furthermore Ideal instructs that ALL devices be "unplugged" or off on the circuit before using the tester.
IMHO they shouldn't be used, period. Especially by one who doesn't read, understand, and follow the listed instructions and labeling for such a device, and if not capable of comprehending the warnings, instructions, conditions and circumstances of a system, shouldn't be investigating in the first place - errors may prove shocking, damaging, or worse, deadly.
Doesn't answer the ? regarding presence of GFCI breakers or GFCI receptacles on the circuit. Doesn't answer regarding possiblity of MWBC, and acknowledges only GFCI protection to outdoor receptacles, which apparently were not a part of of the circuit he was questioning! Mentions presence of GEC at panel - but not addressing or acknowledging possiblity of OPEN GROUND downstream the panel. Makes no reference of confirming "good" ground at receptacle ("outlets"). Has asked similar opening question before. :confused:
Jerry Peck
03-04-2010, 06:07 PM
3-light testers are NOT for use on MWBCs (hot-hot-neutral-ground). Some three-light testers will indicate reverse wiring when actually 240V is present.
I'm still not following you.
You plug a 3-light idiot light tester into a 120 volt receptacle, which has one hot, one neutral, and one ground, the tester is so dumb that all it reads is the hot-neutral-ground like any other receptacle.
*IF* there is a problem, it would not be the three light tester - you referred to 240 volts present, dang, if there is 240 volts present IT SHOULD NOT BE A regular 120 volt receptacle. Any problem would not be the idiot light tester, it would be with the wiring of the receptacle.
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