Reading an article in EC&M magazine, and it starts off by saying "Before the days of electronic loads, equipment grounding conductors (EGCs) were not required at the branch circuit level." I'm not sure what EGCs have specifically to do with electronic loads, but regardless, weren't EGCs always required with branch circuits to quickly remove a dangerous voltage on a metal enclosure? I want to take this article seriously but I can't get past this statement.
EGC question
- Thread starter cppoly
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jumper
Senior Member
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EGCs for branch circuits were not always required. 1947 for the laundry was the first.
http://forums.mikeholt.com/showthread.php?t=111774
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Given that you've stated 1947 the electronic loads mentioned in the OP have nothing to do with the evolution of the EGC.
electrofelon
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Come on guys, don't you know electronics need "clean power" :roll:
jumper
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OP said he did not care about the electronic reference. Just wanted to know about EGCs and branch circuits.
ggunn
PE (Electrical), NABCEP certified
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Many of us are old enough to remember ungrounded (two prong) receptacles. Some of us also remember unpolarized receptacles where the two prongs were the same size.
jumper
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LarryFine
Master Electrician Electric Contractor Richmond VA
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I remember "universal" 2-prong and multi-voltage receptacles with both slots T-shaped, screw-in receptacle adapters, and radio antenna-and-ground receptacle with one slot at an oblique angle.
I have worked in plenty of pre-Civil War homes where a pair of upstairs-hallway floor-boards were pried up to run K&T the length of the house for the downstairs lighting.
Added: Examples:
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LarryFine
Master Electrician Electric Contractor Richmond VA
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I may be a geezer (I'm 62) but I bet I can out-ride most of you on twisty mountain roads on my motorcycle, and it's not even a race-replica style bike.WarningOld Geezer alert ������ ........
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Yes, my comment wasn't directed to your post but I was commenting to the OP. I quoted you because you proved the 1947 reference. Sorry for the confusion.
JFletcher
Senior Member
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No. I take it you've never seen K&T, or a 50s era home with 2 wire cloth NM cable.
although receptacles have had to be grounded for 50-odd years, switches havent had to be grounded until more recently; perhaps late 80s? For a while Slater made a plastic yoke switch that didnt have a ground terminal, but i think those went away mid 90s.
kwired
Electron manager
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Possibly meant that is wasn't common practice to pull a green wire when using metal raceway before the days of electronics? The metal raceway was still an EGC.
LarryFine
Master Electrician Electric Contractor Richmond VA
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- Henrico County, VA
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- Electrical Contractor
I've worked in homes that had circuits that were wired with EGCs in part of a given circuit. For example, an EGC (two gauges smaller) in the cable from the panel to a bathroom, supplying the switch, light, and receptacle, then continuing to a bedroom or two with NO EGC in the cable.
drcampbell
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It also wasn't common practice to pull a green wire before the polio vaccine was available. It's purely a coincidence of timing in the evolution of electric power systems and electronic equipment. The green wire wasn't added because of electronic equipment.
T-slot receptacles are apparently still available, though I can't imagine why I'd ever use one.
https://store.leviton.com/products/...unded-t-slot-ivory-5000-i?variant=18216151427
IIRC, sw/egc was 1999
The best guess is that maybe some people still have equipment w/ the old 120v tandem blade plugs that fit that rec.
Even if that were the case, they shouldn't be installed if you were going by the book---those aren't allowed per the NEC rules on interchangeability.
electrofelon
Senior Member
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Growers like those! From a website:
"This commercial grade Duplex 120V/240V, 15A X-receptacle is ideal for the DIY grow room enthusiast"
kwired
Electron manager
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- NE Nebraska
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- EC
I've seen a lot of 1960's and 70's installations with metal raceway - they never have green wires installed, they do use grounding receptacles though - raceway was and still is considered an EGC. Get into 1980's and you saw green pulled to computer station locations, cash registers, etc. even if they pulled an additional green into existing line.
I think you might find those T slot receps are somewhat common in grow house operations.
Yep---- but the ones growers use are a grounded version of what is shown in the pic above:
Think of a bastardized 5-15 with double t slots----they are from China, aren't listed and are illegal per the NEC.
The Leviton rec shown in the pic is intended for replacement of legacy 2 wire double tees on very old wiring.
K8MHZ
Senior Member
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- Electrician
The transistor was invented in 1947.
Prolly has nothing to do with the EGC, but still......
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