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Q: What is the proper range of household line voltage? ( Answered 5 out of 5 stars,   1 Comment )
Subject: What is the proper range of household line voltage?
Category: Science > Technology
Asked by: markd606-ga
List Price: $5.00
Posted: 24 May 2005 11:40 PDT
Expires: 23 Jun 2005 11:40 PDT
Question ID: 525096
What is the proper range of household line voltage?

I know household line voltage is supposed to be about 120VAC but I
know some variation is normal. Presumably, there's some standard or
some regulation that describes the range of voltages the utility is
supposed to provide.  For example, maybe it's limited to plus or minus
5%, between 114 and 126 VAC.

In particular, I'm measuring 135VAC at my outlets, and I want to know
if I can make the utility fix this.

I'm looking for an answer that spells out requirements for electrical
power that the power utility company is required or committed to meet.
 I'm looking for a link to an authoritative source, like an NEC clause
or an ANSI standard.  (Alternatively, if you are an authority, please
describe your credentials or relevant background that applies
specifically to standards for electrical power distribution.) I'll
double the payment if the source applies specifically to my situation
(I live in Chicago and am supplied by ComEd), such as a compliance
statement by ComEd or an Illinois regulation.
Subject: Re: What is the proper range of household line voltage?
Answered By: sublime1-ga on 24 May 2005 13:36 PDT
Rated:5 out of 5 stars

"(1.051) Voltages specified in this book are nominal and variations
in voltages from nominal values are acceptable within limits (83 Ill.
Admin. Code Part 410). Voltage variations measured at the
Customer's service terminal(s) shall normally not exceed for a
period longer than one minute:

a. 5.8% above or below nominal voltage for service rendered for a
lighting purpose. On the Company's 120V standard, the range of
acceptable voltage is 127 volts maximum and 113 volts

b. 10% above or below nominal voltage for service rendered for a
power purpose."

From 'The Information and Requirements For The Supply of Electric
Service', also known as The Rule Book.

The link is on this page from the parent company of Commonwealth
Edison, Exelon, which discusses residential power:

From the Illinois Administrative Code Index, here:
The Illinois Administrative Code, section 83-410: STANDARDS OF 
governs these standards, and, if satisfaction is not forthcoming
from the power company, one could bring it to the attention of 
the Secretary of State, which oversees the code. Contact page:

The homepage for the Illinois Administrative Code is here:

Another Illinois power company, MIDAMERICAN ENERGY COMPANY,
has a PDF which discusses the protocol for customer complaints
related to this code, and may be useful:

 Complaints concerning charges, practices, facilities or
 services provided by the Company shall be investigated
 promptly and thoroughly. All written complaints will be
 acknowledged in writing or verbally. The Company shall
 keep such records of complaints as required by 83 Ill.
 Admin. Code Part 410.

 If the complaint cannot be resolved at the initial inquiry
 point, the information shall be promptly referred to the
 employee or department who has authority to take appropriate
 action to resolve the complaint. Any complaint, if unresolved
 by the prior action, shall be referred to the appropriate
 management employee for action.

 The final step for any unresolved informal complaint shall
 be a filing with the Consumer Affairs Division of the 
 Commission, by either the complainant or the Company, for a
 resolution of the issue.

 The Company shall maintain a customer call center where
 customers can reach a representative and receive current

 The Company will comply with all service standards and
 reporting requirements as required by 83 Ill. Admin. Code
 Part 410."

The customer service page on the Exelon site, where you can
begin the process of communicating your problem by selecting
Residential and ComEd, is here:

Please do not rate this answer until you are satisfied that  
the answer cannot be improved upon by way of a dialog  
established through the "Request for Clarification" process. 
A user's guide on this topic is on skermit-ga's site, here: 

Additional information may be found from further exploration
of the links provided above, as well as those resulting from
the Google searches outlined below.

Searches done, via Google:

"line voltage" standards "+/-" "Commonwealth Edison"

Commonwealth Edison

"83 Ill. Admin. Code Part 410"

"Illinois Administrative Code"

markd606-ga rated this answer:5 out of 5 stars and gave an additional tip of: $6.25
This is an excellent answer.  It's exactly what I needed, including
the bonus material.  (I tried to accept this answer earlier, but
Google and my browser were fighting.)

Subject: Re: What is the proper range of household line voltage?
From: sublime1-ga on 24 May 2005 21:28 PDT

Thanks very much for the rating and the tip.

I have to say I'm impressed. It's rare that a first-time
customer pays close enough attention to the percentage
of the question price that the researcher keeps, so that
the addition of the tip adds up to double the question
price, as you promised. Very nicely done!  :  )


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