Old wiring types

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wc86

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Could anyone give me a rough idea of how old a house would be to expect knob and tube, bx, and romex(without any updates)? Im in Massachusetts if that makes a difference.
 
Here is a brief timeline:
1985-2024 romex is just like today NM-B 90C insulation.
pre 1985 - 1970 is the more modern wiring era, however that pre 1985 romex can be worse than knob and tube, as it could not take the heat from the old 100W incandescent. Aluminum wiring/busbar from this era had issues. Also breaker panels such as FPE were known to be defective and lost their UL listing.
1962 - 1968 Grounded romex started out but we used the Canadian sized equipment grounds, not all outlets were required to be grounded, it was phased in.

1962 - 1928/26 , I think the bulk of todays old wiring is this era, 100% ungrounded romex, during the war years the quality of rubber went down, BX and knob and tube were still widely used. Plugs and fixtures were standardized but non-grounding types.

1901- 1928/26 You'd see open wiring on insulators, BX, concealed Knob and tube, wooden wiremolding, exposed busbar, RMC, open switches, light fixtures were not required to have have boxes. However overcurrent protection was much more restrictive 6 - 10 amp fuses were common. Switch polarity, system voltage and outlet types were all over the place not as standard as today. 50hz, 40hz, 25hz DC and odd combinations of two phase were used in some places. Gas'o'leers Combination gas / electric lights were not uncommon.

Prior to 1901's definitely either concealed knob and tube, or open wiring on insulators, no bx or greenfield (flex) before this date, fixtures were marked in candle power not watts. Anything you find from this era send me a PM.
 
tortuga said:
Here is a brief timeline:
1985-2024 romex is just like today NM-B 90C insulation.
pre 1985 - 1970 is the more modern wiring era, however that pre 1985 romex can be worse than knob and tube, as it could not take the heat from the old 100W incandescent. Aluminum wiring/busbar from this era had issues. Also breaker panels such as FPE were known to be defective and lost their UL listing.
1962 - 1968 Grounded romex started out but we used the Canadian sized equipment grounds, not all outlets were required to be grounded, it was phased in.

1962 - 1928/26 , I think the bulk of todays old wiring is this era, 100% ungrounded romex, during the war years the quality of rubber went down, BX and knob and tube were still widely used. Plugs and fixtures were standardized but non-grounding types.

1901- 1928/26 You'd see open wiring on insulators, BX, concealed Knob and tube, wooden wiremolding, exposed busbar, RMC, open switches, light fixtures were not required to have have boxes. However overcurrent protection was much more restrictive 6 - 10 amp fuses were common. Switch polarity, system voltage and outlet types were all over the place not as standard as today. 50hz, 40hz, 25hz DC and odd combinations of two phase were used in some places. Gas'o'leers Combination gas / electric lights were not uncommon.

Prior to 1901's definitely either concealed knob and tube, or open wiring on insulators, no bx or greenfield (flex) before this date, fixtures were marked in candle power not watts. Anything you find from this era send me a PM.
Click to expand...
This is very cool! Thanks!
 
readydave8 said:
6-10 amp fuses? Haven't seen that, regional perhaps?
Click to expand...
Prior to the 1923 NEC the maximum fuse allowed on a lighting circuit was 10 amps.
The maximum calculated load for any 10Amp branch circuit was 660 watts and 16 lamp ‘sockets’, outlets were not yet counted.
The minimum wire size was #14, so as fuse boxes got replaced over the years the circuits ended up in 15A breakers.
Edison plug fuses came in all kinds of sizes up to the max size of 30A, so it was (still is) common to see 30A fuses installed later by homeowners.
 
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