Another electrical question

Since you guys like talking about electrical so
much, i've got a question. I do some volunteer
work on an old building built in the 30's. Main
power comes into the building to a main fused
disconnect, then goes to the meter, then from the
meter main lines run through a trough terminating
at the main fuse panel. There is no ground wire.
Between the meter and the fuse panel a lot of
lines tap off the main, to feed heat, water pump,
blower motors, and other circuits. All of them go
through their own fused disconnect before going to
thier destination. Each disconnect has two fuses,
one for the hot and one for the neutral.My
question is, why are all of the neutral circuits
fused? Is this because of the lack of a seperate
ground? all of the cable is either bx or metal
conduit. Yesterday a fuse blew in one of the
circuits. (someone overloaded it, we know why it
blew). We had no spare fuses on hand, so i took
the fuse off of the neutral circuit, connected the
neutrals directly together, put the fuse over on
the black hot side and we were back in business.
Can I leave it like this, or do i need to put a
fuse back in the neutral?
 
The only requirment for a switched neutral [as far as I remember] is to the island at a gas station. If you truly have neutrals in the disconnect fused. If you are sure you are dealing with neutrals and not two hot lines.No violations. Why your neutrals are switched may depend on what type of facility you are in and what the old tenant was doing there.But I have no idea other than mixing large vats of chemicals.
 
Way back all neutrals were fused. I have worked on some of these and sometimes trouble shooting is a nightmare. joe
 

Are these "fused neutrals " really neutrals or are these 240V supplies to 240V loads?
Is there. Desire and a budget for electrical upgrades? Or is the antique electrical service part of the building's heritage ?
Something to check is to make certain wires that are supposed to be "neutral" are really a neutral? Two wire systems are noted for being mixed up.
The neutral is an insulated load current conductor that is held to near earth potential. This keeps the 120V, 240V on 240/416 three phase systems, 277V or 347V line from rising more than 120,240,277 or 347V above earth potential.
The ground is not a load current carrying conductor. The ground system's purpose is to keep grounded and bonded components to near earth potential .
 
Sorry, I have no idea concerning the building,,,,,,,,,,or its uses,,,,,,,,,,,or what (if any likely not lol) codes or regulations may have been used in the thirties at that location,,,,,,,,,,so Im NOT going to speculate whats there or why or how its wired or open a can of worms for people to argue about lol

That being said, in the commercial and industrial and residential locations when and where I practiced we "usually" didn't switch or fuse or open Neutrals.

There were instances where Neutrals were switched, that was if we used a 3 pole transfer switch between the Utility and our own Separately Derived System in a 120/240 volt single phase there wire service.

Without seeing the installation and knowing if indeed Neutrals were switched and fused??????????? and knowing any local authority or rules or the buildings uses, I cant answer you question. If others can given these same circumstances, more power to them. If they know the uses and codes (if any) and location and have the wiring diagrams they may give a more accurate response. You may want to consider consulting with a local trained professional who is there and can inspect the actual situation.

John T
 
john t off subject from a bubba. I was told at one time if bx cable or metal conduit was used in a system it is considered the same as a ground circuit and should not be disconnected or isolated at any time except as need be for component replacement and must be reconnected when repair is completed. the above post mentions bx and conduit. your comments please.
 
There are indeed situations where certain types and brands of conductive metal conduit can suffice as the Safety Equipment GroundiNG Conductor fault current return path.

HOWEVER, to do so all the correct bonds and splices and terminations and fittings MUST be used and properly installed AND THATS IMORTANT AND STRICT AND DEMANDING. I never liked that system but preferred instead, a separate enclosed conductor, that was easier for the electricians, although perhaps a bit more expensive to run more copper.

ITS INDEED TRUE (think about it, its a no brainer) IF THAT ELECTRICAL CONNECTION AND CONTINUITY IS EVER BROKEN, IT MUST BE REPLACED BEFORE OPERATION IS RESUMED because otherwise there's no safety Equipment GroundiNG Conductor path to provide a dedicated low impedance return path for fault current to trip a breaker.

Those are good and legitimate questions I think and I'm glad to help if I can, yes I ranted above about some of the Billy Bobs out there who frustrate me, but all in all Im glad to help.

NOTE Im rusty on this stuff, Im NOT up on the latest codes and practices, however, there are several trained professional electricians out there who are far more current then I am so listen to them also, my old Hard Drive brain is pretty full lol

John T
 

There was a time when electrical conduit or the sheath of armoured cable was considered a ground path.
Today the conduits and sheath of armoured cable will be bonded to earth only at the supply end.
A separate and appropriately sized ground wire will be pulled into the conduit with the live lines and neutral if used.
 
In my area nothing is grandfathered on a public building. The electrical would need to pass the same standards a brand new building would. I think you need a local electrician to fill in the blanks.
 
With the exemption of switching a neutral in a generator transfer switch where the generator is internally bonded. The neutral is NEVER switched or fused. The ground is never switched or fused in any circumstances.
 
ok....these are definitely neutrals. I may not be a pro but I've done a lot as an amateur and know the difference.
the circuit in question is a 120v. all of the original recepticles in the building are 2 wire.
Over the years I've added a couple of sub-panels wired into the lines in the trough after the meter. On those panels I ran a ground wire back through the trough and tied it down to the metal cabinet that the meter is in. May not be correct, but I thought it was better than nothing. All of this is on the second floor, so sinking a ground stake in would not be a simple option. The building originally was a small town, down town single screen movie theater built during the depression. Built cheaply, I might add.
 
I've seen many old buildings that had fused neutrals. Worked on a house once that had 4 Edison type fuses. 1 for incoming hot, 1 for incoming neutral, 1 for the furnace, 1 for the rest of the house(house only had 120volt service). In the older buildings it was also common to use the conduit for a ground path, an old service that I changed out had 3 phase high leg 200 amp service fed with 3 wires. That meant the conduit was also the neutral, scary. When the neutral is fused it can really get bad because the wrong side of the fuse is hot when the fuse is blown(also the case on 240/277/480) and because someone, somewhere, might have used the neutral for a ground too.
There was a system used in center pivot irrigation some time back that was a 3 phase corner ground delta. The issue was that 1 phase not only was fed to the motors, but it also was grounded to the equipment and earth ground. Typically when they did this they would run all 3 wires to a 3 phase fused disconnect. In the center spot they would use a piece of 1/2" copper pipe. Some do gooders(under educated/experienced electrician) would see this and see it as a farmer modification for a fuse that kept blowing and replace it with a fuse. What would happen next is that this fuse would blow thereby making the outer case of the fuse box "hot" with I believe 277 volts. When someone tried to check the fuses they would get shocked/electrocuted when they tried to open the door on the fusebox.
 
I don't know why you add code information when you don't even live in the same country as everyone else and obviously use a different code book or don't read the one you have very well. So go read 514.11 Circuit Disconnects . Obviously you have never wired a gas station.
 
IIRC in fuel dispensing emergency shut off
situations then all conductors are
disconnected, even communication wires.
But maybe I'm wrong.
 
(quoted from post at 20:22:20 12/08/14) IIRC in fuel dispensing emergency shut off
situations then all conductors are
disconnected, even communication wires.
But maybe I'm wrong.

Section 20-040 Circuit Disconects. Quote " each circuit leading to or through a propane dispensing device or pump shall be provided with a switching means that will disconnect simultaneously all UNGROUNDED conductors of the circuit from the source of supply" unquote.
 
That is what I mean . There is no section 20-040 in an NFPA NEC codebook.If you read the section I posted you would read that in fuel dispensing the neutral is switched. You are quoting a code book for Canada. Nobody cares how they do it in CANADA.
 
(quoted from post at 13:49:51 12/09/14) That is what I mean . There is no section 20-040 in an NFPA NEC codebook.If you read the section I posted you would read that in fuel dispensing the neutral is switched. You are quoting a code book for Canada. Nobody cares how they do it in CANADA.

You mean that country with healthcare and the low murder rate ? The country that sells all those maple leaf flags that Americans sew onto their luggage and clothes before travelling to foreign countries . The country that hauled US hostages out of Iran? The country that supplies the US with more oil than the Middle East? The country that less national debt per capita than the U.S.? The county that takes low cost luxury vacations to Cuba ?
The NEC covers both countries .
Tell me mr.electrical engineer. How is not switching ungrounded conductors a problem .
 
You obviously did not read the code section I referred to . I don't claim to be an electrical engineer either. I don't talk about electrical work . I don't draw do drawings of electrical work . I DO electrical work. Throw all the insults quote all the BS theory you want you only make yourself out to be a bigger jerk off every post.Obviously your code book is not the same as a few weeks ago you stated it was a violation to use conduit as a ground. If you are mistaken you never admit it.
 
(quoted from post at 15:24:14 12/09/14. I don't claim to be an electrical engineer either. I don't talk about electrical work . I don't draw do drawings of electrical work . I DO electrical work.

Just great . Another know it all jackleg electrician that won't listen who is wiring equipment that he doesn't understand.
 

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