Loop Systems and Chicago Electrical Code

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Paul M Lurie

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Mike Langer from the Hearing Loss Assocation of America Loop Group referred me to you.



I am a partner in a large law firm headquartered in Chicago's Willis (Sears) Tower. As a member of its disability committee, I convinced the firm to start looping our many conference rooms with under carpet wiring over concrete floors. We want to start in our Chicago office. We are doing this not just to accommodate our lawyers and staff, to advertise the loops to others who visit the office. We intend for this to be a important way to promote loops.


HOWEVER, I was told by Keith Hall, electrical head of the City of Chicago Building Department ,that all wiring under carpets must be in conduit or equivalent. Apparently he has not directly confronted the issue of low voltage loop wiring as an exception. Mr Hall was receptive to being convinced that loop wiring is not the same safety issue as 120V wiring.


I am looking for evidence that other building code departments allow loop wiring under carpeting and why they do not consider it a safety issue. My law specialty is construction so I am quite familiar with code variance process. Once we get the variance we need to get the Code amended. Any suggestions about that? Do you know of other cities have this antiquated code provision and had it amended.


Thanks,

Paul
 

ron

Senior Member
Does the loop circuit have to be a certain conductor or twist to make it work? Can it be a CMUC rated cable?

FYI
The NEC has an entire Article 324 Flat Conductor Cable for power line voltage: Type FCC is a wiring system designed for installation under carpet squares.

NEC Section 725.154(E)(6) Type CMUC undercarpet communications wires and cables shall be permitted to be installed under carpet.
 
I realize that it's not the same, and I don't know how well it would work, but can you mount a loop under the edge of a conference table? They generally have low-voltage wiring, anyway (phones and network). That would place it closer to most of the users and be far easier to install.

However... consider the privacy and confidentially issues- unless you somehow block the loop's radiation, which may not be easy, it will be possible to pick it up from outside the room and maybe even from the floor below or above. That's effectively adding your own 'bug' to the room. Kind of wrecks having a privileged conversation.

While induction loops are great, you might consider IR-based systems instead.
 

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
PE (Retired) - Power Systems
Chicago doesn't follow the NEC.... they follow their own home-brewed rules.

Not more so than many other locations.

The Chicago Electric Code is based on the 1999 NEC. They do insist on NRTL Listing. (of course UL is preferred).
They accept some undercarpet communication wiring ( type CUMC per 18-27-800.50).
 

480sparky

Senior Member
Location
Iowegia
Not more so than many other locations.

The Chicago Electric Code is based on the 1999 NEC. They do insist on NRTL Listing. (of course UL is preferred).
They accept some undercarpet communication wiring ( type CUMC per 18-27-800.50).

'Splain my 1930 Chicago code then.
 
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