no more networking?

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slc410

Electrician
Location
Madison wi
Occupation
Electrician
I was told today that on a 120/208 4 wire system we can no longer network phases (share neutrals). Each ungrounded conductor must have its own neutral within the conduit which only gives 4 circuits in a 3/4 conduit before derating. WHA?????
 
slc410 said:
I was told today that on a 120/208 4 wire system we can no longer network phases (share neutrals). Each ungrounded conductor must have its own neutral within the conduit which only gives 4 circuits in a 3/4 conduit before derating. WHA?????
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Still NEC legal. But check 210.4(B) and (D). Maybe that what the person who told you this is referring to.

Either that, or it's a job spec.
 
MWBC"s are still permitted although the 2008 NEC has added further requirements regarding the simultaneous disconnect of all circuits sharing a neutral. To say that sharing neutrals is no longer permitted is not an NEC requirement.
 
Many of our clients are telling us to design their systems without shared neutrals, specifically because they don't want to have to turn off three circuits in order to work on one. But that is only for those clients in areas that have adopted the 2008 NEC. That is the first edition that required MWBC (or "networks," or "full boats") to be served by overcurrent devices that turn off all circuits at the same time.
 
I would like to strongly urge that the words "Network" and "Networking" NOT BE USED to describe a shared neutral situation.
Please Do Not Do It.
thanks
db
 
480sparky said:
Networking is a new use for the word to me..... I always call it 'sharing the neutral' or MWBC.
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Could have been derived from "network" service.

A 3-wire service consisting of two ungrounded conductors and the neutral from a 4-wire wye system is called a 3-wire network service.

For example, the 120/208 network service is actually two, 120 volt, two-wire, single-phase circuits that share a neutral. The two 120 volt circuits have a 120 degree phase difference.

I have never heard the term "networking" when talking about a 3-phase service but I haven't heard everything yet.
 
A 3-wire service consisting of two ungrounded conductors and the neutral from a 4-wire wye system is called a 3-wire network service.
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Says Who??
Use that term around here and people will think 'computers', 'server racks', 'I.T. Guys'.
Thirty Plus years in Commercial, Industrial, Institutional - Never heard it.

There are enough poorly defined, unnecessary slang terms in this industry without adding another.

db
 
barclayd said:
Says Who??
Use that term around here and people will think 'computers', 'server racks', 'I.T. Guys'.
Thirty Plus years in Commercial, Industrial, Institutional - Never heard it.

There are enough poorly defined, unnecessary slang terms in this industry without adding another.

db
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One person hardly has the breadth and expertise to be able to distinguish everything that is and is not slang. We are limited by our own travels and experiences.

As for the network service term:
Says the bible reference for electricity metering that has been around since 1912. The handbook is currently edited & published by the Edison Electric Institute which has been around since 1933.

This is an industry recognized standard and reference authored by industry leaders and reviewed by experts in the field from around the world.

Get yourself a copy as it is a great resource:
http://www2.eei.org/products_and_services/descriptions_and_access/handbook_meterng.htm
 
mivey said:
As for the network service term:
Says the bible reference for electricity metering that has been around since 1912. The handbook is currently edited & published by the Edison Electric Institute which has been around since 1933.
This is an industry recognized standard and reference authored by industry leaders and reviewed by experts in the field from around the world.
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The original post was refering to a Multi-Wire Branch Circuit, not a Service. The word 'network' was used as a verb. Yuck - reminds me of counseling ... 'Let's dialog, shall we?'

Not that I've ever been to counseling ... or needed counseling.

"Let's network these wires to make a MWBC" NO, NO, NO!!!!

db
 
charlie b said:
That is the first edition that required MWBC (or "networks," or "full boats") to be served by overcurrent devices that turn off all circuits at the same time.
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To be more accurate, it's manual disconnection that requires simultaneous de-energization. Simultaneous OCD is only required for MWBC's with line-to-line loads.

Of course, these days, almost all installations use a breaker for manual disconnect, too. I just wanted to keep Charlie on the straight and narrow. :wink:
 
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