Old ('65) feeder

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augie47

augie47

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State Electrical Inspector (Retired)
Question has come to light concerning an existing residence wired around l965 that has two interior panels fed from outside disconnects using a 3 wire SE cable.
Was a 4 wire feeder required in that era ??
 
Thumbing through some archives on web. So far latest one 1965 the report stated that grounded conductor was not permitted for grounding. Will be searching more as find this situation quite frequently in this area also. Have heard it has been a requirement for a very long time, just not enforced properly.
 
If it is in the same structure, it is my understanding that a 4-wire feed to a subpanel was always required. Separate structure/building a 3-wire used to be allowed but was changed to not allow it around the 2008 I believe.
 
augie47 said:
Question has come to light concerning an existing residence wired around l965 that has two interior panels fed from outside disconnects using a 3 wire SE cable.
Was a 4 wire feeder required in that era ??
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As far a I can tell from research, it has not been allowed for a very long time. At least as far back as the 1930 NEC. Before that the NEC is hard to follow and understand the language, IMO.
 
augie47 said:
Question has come to light concerning an existing residence wired around l965 that has two interior panels fed from outside disconnects using a 3 wire SE cable.
Was a 4 wire feeder required in that era ??
Click to expand...
I love a history question, 250-23 of the 1965 code would prohibit this if there were main breakers.
if it originally was just a meter they could have been interpreted as separate services. Article 100 note to definition of a service (in 1965) ;
"A meter is not considered a part of the service equipment"
 
There are two service disconnects at the meter so these are feeder conductors. In 1965 this was not permitted.
 
augie47 said:
Question has come to light concerning an existing residence wired around l965 that has two interior panels fed from outside disconnects using a 3 wire SE cable.
Was a 4 wire feeder required in that era ??
Click to expand...
are the disconnects as old as the cables or were they added sometime later?

Seen many cases where they entered with service cable quite some distance as well, and this rule is still pretty vague today, and mostly up to local jurisdictions as to what they will allow.
 
We see this every so often over here. I remember asking the question several years ago, and also remember being told the same thing. It's never been a legal installation. I'm not sure why so many folks installed 3 wire feeders to subpanels back in the day then?? Maybe SER wasn't available?
 
ser probably wasn't available around here in the early '90s I remember the only way to do mobile home hookup was 3-conductor AL URD with separate bare copper for ground, nobody sold 4-cdtr urd
 
I agree. Not legal but common practice.

A buddy of mine (who's licensed) was changing a service for a duplex side by side I wen tover to give him a hand. The side the service was on it came down to the meter socket then one cable into the building to a MBP just like a normal house. The other dwelling unit they had a 2 pole disconnect outside fed from the meter and he ran 3 conductor SE through the house to a main lug panel. I said why did you do that you need 4 wire SER. He left it and it passed inspection . This was about 10 years ago
 
readydave8 said:
ser probably wasn't available around here in the early '90s I remember the only way to do mobile home hookup was 3-conductor AL URD with separate bare copper for ground, nobody sold 4-cdtr urd
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That would be a supply/demand issue at work there. Nobody buying it means suppliers aren't stocking it. We definitely had 4 conductor URD before then. Real common for three phase on the farms then, some for 2800 foot runs to irrigation equipment. None of it at that time was dual rated and acceptable for indoor use - nobody caught on to that until about mid 90's though. Eventually there was enough demand the suppliers started stocking dual rating on certain sizes though.
 
readydave8 said:
Yes I remember asking counterman why they didn't stock 4/cdtr and that was the answer. So I'd say, "Of course no one is buying it, you don't have any"
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But if enough ask for it maybe they change their minds?

If the other supply house across the street sells a lot of it that should maybe be a good reason to start stocking it? (Seems funny how supply houses are always just across the street or only a block or two away from one another, or if you see McDonalds there is probably a Burger King pretty close as well. Same with Walgreens and CVS.
 
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