Antique equipment

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nizak

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Recently I was doing some renovation work in a commercial building(100+years old) and ran across a knife switch that was located in a closet. It was no longer in use but the patent date on it was 1901. Appears back in the day both the hot and grounded conductors ran thru the switch, why would the neutral be broken? Anybody else here found any traeures lately?
 
nizak said:
Appears back in the day both the hot and grounded conductors ran thru the switch, why would the neutral be broken?
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I find disconnects with neutrals switched every once in a while, usually its a three phase disconnect being used on somthing that needs a 2pole disconnect and there is no neutral lugs, so Im assuming they are using the third pole instead of a wirenut or a neutral bus kit, its never a good Idea to switch a neutral ....
 
ultramegabob said:
.... its never a good Idea to switch a neutral ....
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That's not true at all.

Sometimes it's even NEC required. Circuits to gas station islands, for instance, need switched neutral breakers.
 
mdshunk said:
That's not true at all.

Sometimes it's even NEC required. Circuits to gas station islands, for instance, need switched neutral breakers.
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Well, I guess I just learned something today, I have never been required to switch a neutral on anything before, but have ran into many problems caused by swithched neutrals that someone else did...
 
ultramegabob said:
Well, I guess I just learned something today, I have never been required to switch a neutral on anything before, but have ran into many problems caused by swithched neutrals that someone else did...
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You also didn't start electrical work in 1901. :wink:

You certainly may open neutrals, as long as the device opens all conductors simultaneously.
 
cpal said:
I wouldn't be surprised to find the original wiring was DC
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I had a house once that was built in 1906, it was indeed originally wired for DC power. It was about 2000' from an old DC power generation station in Seattle (now called Gasworks Park because they preserved all of the old machinery as playground equipment).

http://blog.lib.umn.edu/mart1711/architecture/Picture 4.png

It too had knife switches that broke both lines and I could tell that the original AC service brought in was wired to the same switches for a while. When someone did the upgrade in the 1950's for electric baseboard heating, they abandoned all the old knife switches and knob and tube wiring, but left it in place so I could see it all later when I remodeled. Fascinating system really, I had fun trying to figure it all out before I covered it up again.
 
I'm wondering if they even grounded the services back then.

No ground, no neutral. Both wires would be hot.
 
In the old days, services were often just (2) plug fuses and (2) single pole knive switches. Conductors were not regularly grounded. It was not uncommon for one main feeder to be run on one side of the house and the other conductor on the other side with taps running to the outlets mounted in the middle.
 
mdshunk said:
That's not true at all.

Sometimes it's even NEC required. Circuits to gas station islands, for instance, need switched neutral breakers.
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i think hes thinking about switching the neutral with an ATS. thats not a very good idea because if the switch is off a split second you can fry stuff:grin:
 
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