Messages Archive

Re: Clarification
Response To:
220 = 2- 110 ()

Larry Clinton At Frankfort, (Central) Indiana
First, codes in some areas require that the Neutral (the white wire that comes from the Utility service) be grounded to the entrance panel ground. In other areas that is not only not required but banned! Earth grounds are actually needed by the power companies to keep the "hot" lines from "floating" and having a higher potential than the normal 120V to the ground. The Floating is caused by capacitance and induction from the other lines in the system.

Second the "Earth ground" is not intended to carry any current in normal use. It is only there to keep the "grounded" portion of 3 prong plugs at the potential of the earth and prevent shocks to users. in the case of a short the "earth ground" will cause the breaker/fuse to open.

Third, the 120V power in a standard home is measured from the neutral to either of the 2 hot lines. Power input to these homes is a sine wave at 60 Cycles per second and the potential (voltage) on one hot line is 120V RMS "Above" the neutral/ground and the other hot line 120V RMS "Below" the neutral / ground. The 240 Volt power is obtained by measuring between the two "hot" lines. In a properly functioning 240V circuit NO POWER is carried on the neutral / ground.
(Explanation of RMS these letters stand for Root Mean squared and is a formula for measuring the usable potential voltage. The actual peak voltage of the sine wave is quite a bit above the 120v or 240V description.

As to the neutral carrying an excess load in a split circuit when both circuits are under load it in not true. If both circuits are carrying the same load, again there is no current carried by the neutral!

Now as to your initial question, you can legally split a 240 Volt circuit into two 120V circuits, however this is only to code If THE EXISTING WIRING HAS 4 CONDUCTORS AND YOU CHANGE THE BREAKERS. If the existing wire feeding the 240 V outlet has 2 hot lines (normally a black and a red) a White neutral and a Bare Copper ground then it is to NEC code. If it doesn't have the 4 wires then you cannot,

I do wish to caution everyone here that electrical wiring should not be done without proper knowledge. There are a lot of people that have some knowledge of wiring and believe they have answers to your questions, often that information is incorrect and in some cases dangerous. If you are not sure of what is to code and know how to do the wiring it is a whole lot less expensive to hire a qualified electrician than to burn your home down or electrocute someone!

© 1998 - 2017 by Ellis Walentine. All rights reserved.
No parts of this web site may be reproduced in any form or by
any means without the written permission of the publisher.