A little History on these: All are from three different parts of a Church complex dating from 1962, 1965, and 1975
PIC#1- The switches are 1.) Sierra electric outlet from the 1950s or so and had rather odd terminals. It was a "leftover" that was handy to replace a 1965 slater quiet switch that failed (which is in the rest of the building). 2.) pass and seymour residential switch circa 1989 (pastor's house) 3.) Slater quiet switch circa 1965 4.) Two slater outlets...one from 1965, and the other from 1975 addition
I've found those Arrow-Hart T slots in homes from the 1920's actually, and I don't think I've seen them in anything newer than the mid 50's... (I've got probably 30 or so of those in a box in the garage )It's entirely possible someone had this laying around and installed it in 1962 though... There's rust poking through the 710 layers of paint on it as well, Was the t-slot on an exterior wall or a damp location Matt?
#153382 - 01/05/0702:06 AMRe: Some "Historical" Electrical Finds
I do have a fair handful of T-Slots, from various manufacturers (Leviton, Circle F, AH&H, Paulding, etc). I also have one of the Slater quiet switches hanging around somewhere. I removed it from a home back in FL that was being torn down. (yes I got permission to remove said device). The first T-Slot I ever had, was an AH&H that I salvaged from a thrift store dumpster back in FL where I lived. I still have it to this day.
#153383 - 01/17/0701:58 AMRe: Some "Historical" Electrical Finds
Given that the requirement for grounding receptacles first became universal with the 1962 NEC (and universal enforcement probably took awhile), I have no problem believing the T-slot pictured here is from 1962. I don't know what year they stopped making T-slots. They seem to have been phased out in the '50s as industry standards changed to differentiate between parallel slots for 125V and tandem for 250V, but I don't know when they became illegal to use. I do know this: somewhere, I have a 1996 Leviton catalog listing NOS T-slots.
Coincidentally, the oldest part of my church was completed in 1962. I think there are still one or two T-slots in that building.
[This message has been edited by yaktx (edited 01-17-2007).]
#153384 - 01/27/0702:12 AMRe: Some "Historical" Electrical Finds
My grandfather bought a ranch house that was built in the early 60's, it had ungrounded t slot duplex receptacles in every room except the kitchen and garage which had the 20 amp grounded duplex t slot receptacles.
#153385 - 01/27/0710:58 PMRe: Some "Historical" Electrical Finds
The 1959 NEC required receptacles to be grounding type and grounded in the following locations:
...laundry rooms, open porches, breezeways, basements, cellars, work shops, garages, on the exterior surfaces of outside walls or in like locations where the outlet may supply equipment used by persons standing on the ground or on grounded conductive materials.
Also, an outlet installed near the kitchen sink was required to be of the grounding type. (This no doubt was intended to serve the portable roll-away dishwashers that were popular at the time.)
Dawg, it seems like your grandfather's house was built before that jurisdiction adopted the 1962 NEC.
Incidentally, no receptacles were then required in the garage or anywhere outdoors, so these were strictly optional. A "code-minimum" house in 1959 would have had exactly two grounding receptacles.
#153386 - 01/31/0707:35 AMRe: Some "Historical" Electrical Finds
A "code-minimum" house in 1959 would have had exactly two grounding receptacles.
I think we may have discussed this before, but I can't remember the answer. Was the 12 ft. spacing rule for receptacles in force in 1959? (i.e. no point on a wall more than 6 ft. from an outlet). Non-grounding recepts. only required, of course.
#153387 - 02/09/0709:42 PMRe: Some "Historical" Electrical Finds
A short, and by no means exhaustive, history of residential receptacle requirements, at least as far back as my NEC collection goes:
1940: One receptacle for every 20 linear feet of wall space. At least one receptacle for laundry appliance.
1947: Laundry area shall have at least one three-wire receptacle, with the third contact reserved for equipment grounding.
1951: NEC Handbook becomes more specific as to the precise type of three-wire receptacle required in laundry area; includes illustration of what we now call a 5-15R.
1956: One receptacle required for every 12 linear feet of wall space.
1959: No point along the floor line of usable wall space more than 6 linear feet from a receptacle. The receptacle closest to the kitchen sink must be of the grounding type. No receptacles are required outdoors or in the garage, but if installed, they must be of the grounding type.
1962: All 120V and 240V 15A receptacles, in all occupancies, to be grounding type.
1971: A kitchen counter space 12" or wider requires a receptacle. Receptacles rendered inaccessible by fixed appliances do not count as meeting the minimum requirements of 210-22(B).
1975: At least one receptacle required in each of the following locations: bathroom, adjacent to the sink; outdoors if single-family home; basement; attached garage. All 120V 15A and 20A receptacles in bathrooms and outdoors require GFCI protection.
1987: Each receptacle within 6' of the kitchen sink is required to have GFCI protection.
1990: Receptacles serving kitchen countertops are required to be spaced no more than 48" apart, so that no point along the backsplash is more than 24" from a receptacle (excluding areas behind sinks and ranges).
1996: All receptacles serving kitchen counters to be GFCI protected.
[This message has been edited by yaktx (edited 02-15-2007).]