Reply
 
Thread Tools Display Modes
 
Old 09-29-2013, 06:19 AM   #21
FF
Guru
 
FF's Avatar
 
Join Date: Oct 2007
Posts: 16,525
<There is the "separately derived source" rule but it only applies if the neutral is ungrounded, which is almost never the case. There are situations where you need to switch the neutral, but they are few and far between for land based systems.

I work with probably a thousand (I do not count them) installations a year, on a nationwide basis and switch the neutral in less than probably 20 of them.>

I guess the 20 are boats.

The neutral is grounded at the source , for the dockside powerhose its somewhere in the boat yard electric system.

For a noisemaker IT is the source , so the neutral will be grounded there.

Same for an inverter , IT is the source so is internally grounded.

The neutral and ground for a dirt house line are kept apart .

IF the neutral and ground are combined at either the noisemaker or inverter this must be accounted for in the transfer mechanism.

A complex transfer box or a $6.00 plug.
__________________
Advertisement

FF is offline   Reply With Quote
Old 09-29-2013, 09:52 AM   #22
TF Site Team
 
ksanders's Avatar
 
City: SEWARD ALASKA
Country: USA
Vessel Name: LISAS WAY
Vessel Model: BAYLINER 4788
Join Date: Feb 2011
Posts: 3,954
Quote:
Originally Posted by FF View Post
<There is the "separately derived source" rule but it only applies if the neutral is ungrounded, which is almost never the case. There are situations where you need to switch the neutral, but they are few and far between for land based systems.

I work with probably a thousand (I do not count them) installations a year, on a nationwide basis and switch the neutral in less than probably 20 of them.>

I guess the 20 are boats.

The neutral is grounded at the source , for the dockside powerhose its somewhere in the boat yard electric system.

For a noisemaker IT is the source , so the neutral will be grounded there.

Same for an inverter , IT is the source so is internally grounded.

The neutral and ground for a dirt house line are kept apart .

IF the neutral and ground are combined at either the noisemaker or inverter this must be accounted for in the transfer mechanism.

A complex transfer box or a $6.00 plug.
FF, we are discussing land based systems here. Lets keep tyhe discussion to land based systems to avoid confusing people.

Here's a quotation from the NEC Article 250.20D

"An alternate alternating current power source
such as an on-site generator is not a separately
derived system if the neutral is solidly interconnected
to a service-supplied system neutral.”


This is the basis of why on a land based system we do not have to switch the neutral for most backup generator installations.
__________________

__________________
Kevin Sanders
Bayliner 4788
Seward, Alaska
www.mvlisasway.com
ksanders is offline   Reply With Quote
Old 09-30-2013, 05:43 AM   #23
FF
Guru
 
FF's Avatar
 
Join Date: Oct 2007
Posts: 16,525
Here's a quotation from the NEC Article 250.20D

"An alternate alternating current power source
such as an on-site generator is not a separately
derived system if the neutral is solidly interconnected
to a service-supplied system neutral.”

Quite correct as most dirt houses tie the neutral to a water pipe ground .

Not a good idea on a boat.
FF is offline   Reply With Quote
Old 09-30-2013, 09:48 AM   #24
TF Site Team
 
ksanders's Avatar
 
City: SEWARD ALASKA
Country: USA
Vessel Name: LISAS WAY
Vessel Model: BAYLINER 4788
Join Date: Feb 2011
Posts: 3,954
Quote:
Originally Posted by FF View Post
Here's a quotation from the NEC Article 250.20D

"An alternate alternating current power source
such as an on-site generator is not a separately
derived system if the neutral is solidly interconnected
to a service-supplied system neutral.


Quite correct as most dirt houses tie the neutral to a water pipe ground .

Not a good idea on a boat.
FF, the proper way to ground the neutral on a residence is to use ground rods, two of them is better.

Something people do not realize is that the power company grounds the neutral at every pole. Thats the little ground wire stapled to the side of every pole, it grounds the neutral.

On the secondary side of the power transformer, the neutral is also grounded.

In the power world, if its not energized, its grounded.
__________________

__________________
Kevin Sanders
Bayliner 4788
Seward, Alaska
www.mvlisasway.com
ksanders is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





All times are GMT -5. The time now is 02:16 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012