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#98728 - 03/08/05 11:27 AM Section 427.27, Exception
Joe Tedesco Offline
Member
Registered: 10/07/00
Posts: 2749
Loc: Boston, Massachusetts USA
Impedance Pipeline Heating Systems

HELP!

What is the GFP required here in Section 427.27, Exception?

I know it is not a GFCI. but I cannot find it in the UL Directory.

It is a Ground Fault Protection of Equipment.

First one who calls me within the next 1/2 hour will win a prize!

617-818-7627
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Joe Tedesco, NEC Consultant
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#98729 - 03/08/05 05:14 PM Re: Section 427.27, Exception
cpal Offline
Member
Registered: 05/17/04
Posts: 162
Loc: Cohasset MA
427.27 Voltage Limitations.
Unless protected by ground-fault circuit-interrupter protection for personnel, the secondary winding of the isolation transformer connected to the pipeline or vessel being heated shall not have an output voltage greater than 30 volts ac.
A new exception has been added for industrial locations. These units are manufactured as a system and in some cases heat fluid within pipes up to 6 miles long. This is accomplished by regulating currents upwards of 3000 ampere through these vessels. The conductive piping exchanges heat via the I2 R losses and this method is less than others. The transformers are 120/208V and the + - taps are set at 10%, thus the need to increase the output voltage to 132V. Exception: In industrial establishments, the isolation transformer connected to the pipeline or vessel being heated shall be permitted to have an output voltage not greater than 132 volts ac to ground where all of the following conditions apply:
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#98730 - 03/08/05 05:49 PM Re: Section 427.27, Exception
Joe Tedesco Offline
Member
Registered: 10/07/00
Posts: 2749
Loc: Boston, Massachusetts USA
Thanks, this is the part in the Exception that I want to find out more about.

Quote:
(2) Ground fault protection of equipment is provided.


I am looking for this type of protection as described in the UL White book.

When I posted the question, I was discussing this at a class in Pittsburgh, I thought I would see if someone would actually call me with that information.

Charlie you won a beer on me some time in the future.
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Joe Tedesco, NEC Consultant
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