Re: Earth Potential Equalizing
Good Morning Janne! It has been my experience that units seperate from the control cabinet that supplies power to them are grounded to the same ground potential as the the cabinet, assuming you are not using an IT type power system (which is what is used in the Nordic countries for example) where the PE is seperated from true ground by protective impedances. IEC 60204-1 indicates that all parts of equipment should have earth continuity back to the primary earth stud/connection. In fact, section 19 gives testing requirements for this to be 0.1 ohms or less. I hope this helps. Please email me if you need specific data. Regards, Frank West Sr. Engineer TUV Rheinland NA --- Janne_Engström janne.engst...@ivtg.se wrote: Hi all, We are manufacturing heating equipment for industrial use. Our equipment is one part in an in line setup of machines. We are required, by one company we deliver to, to provide a wire for equalizing the earth potential between our control cabinet and the frame of the main machine. The heater is about 50kW at 400V. The required wire is 35 square millimeters copper wire. The equiment in this case is for the European market. I think what they are afraid of is that current will flow in the shields in the control cables between the different parts of the setup, creating problems. Are there any standards that require this? Is this standard procedure? Best regards Janne Engstrom - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). __ Do You Yahoo!? Bid and sell for free at http://auctions.yahoo.com - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Earth Potential Equalizing
In the industrial equipment world, covered by standards such as UL508 and UL347, as well as IEC 60204, it is standard practice to provide a ground conductor that is of sufficient size that the potential of the equipment ground bus, under foreseeable ground fault conditions, does not rise to a hazardous decisive voltage. In practice, this means ensuring that the resistance of the ground path is low enough to ensure that the rise in potential is less than, say, 50 volts (although we use a figure of 24 volts for safety) before either the upstream protection operates, or after the current level reaches short-circuit fault levels (which is the safer course, but may not be practical in all cases when dealing with heavy equipment). The 35 sq.mm ground wire size that you specify is probably not an unreasonable requirment at 500kW, but it depends on the ground loop resistance at the lengths that you are using. Chris Gilks -Original Message- From: Janne Engström janne.engst...@ivtg.se To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Sunday, November 21, 1999 1:26 PM Subject: Earth Potential Equalizing Hi all, We are manufacturing heating equipment for industrial use. Our equipment is one part in an in line setup of machines. We are required, by one company we deliver to, to provide a wire for equalizing the earth potential between our control cabinet and the frame of the main machine. The heater is about 50kW at 400V. The required wire is 35 square millimeters copper wire. The equiment in this case is for the European market. I think what they are afraid of is that current will flow in the shields in the control cables between the different parts of the setup, creating problems. Are there any standards that require this? Is this standard procedure? Best regards Janne Engstrom - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Earth Potential Equalizing
EN 60204-1 Clause 8 covers Equipotential bonding. -Original Message- From: Janne Engström janne.engst...@ivtg.se To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Sunday, November 21, 1999 1:26 PM Subject: Earth Potential Equalizing Hi all, We are manufacturing heating equipment for industrial use. Our equipment is one part in an in line setup of machines. We are required, by one company we deliver to, to provide a wire for equalizing the earth potential between our control cabinet and the frame of the main machine. The heater is about 50kW at 400V. The required wire is 35 square millimeters copper wire. The equiment in this case is for the European market. I think what they are afraid of is that current will flow in the shields in the control cables between the different parts of the setup, creating problems. Are there any standards that require this? Is this standard procedure? Best regards Janne Engstrom - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
