Re: [PSES] grounding of output of solar inverter

2016-02-16 Thread Boštjan Glavič 
Brian,

Thank you. I have learned that Neutral is not needed to be disconnected during 
anti-islanding operation. So output conductor (Neutral) remains grounded also 
during stand-alone operation.

Thank you all for your support.

Best regards,
Bostjan

-Original Message-
From: Brian O'Connell [mailto:oconne...@tamuracorp.com] 
Sent: Tuesday, February 16, 2016 6:59 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] grounding of output of solar inverter

Also, should have noted to reference the NDs in UL62109-1, which further 
addresses below requirements, as stuff in North America is (finally) being 
harmonized at both building code and equipment standards levels.

See this:
http://publicaa.ansi.org/sites/apdl/Documents/Standards%20Action/2016-PDFs/SAV4704.pdf

Brian

-Original Message-
From: Brian O'Connell [mailto:oconne...@tamuracorp.com]
Sent: Tuesday, February 16, 2016 9:28 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] grounding of output of solar inverter

Reference articles 250 and 690 of the NEC (NFPA70). Canada and Mexico code 
similar.

Brian

From: Boštjan Glavič [mailto:bostjan.gla...@siq.si]
Sent: Monday, February 15, 2016 9:05 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] grounding of output of solar inverter

Dear experts,

Is anyone familiar with UL 1741? I am dealing with solar inverter for US 
market. Solar inverter can operate in utility interactive mode (feeding the 
grid) or in  a standalone mode where only homeloads are supplied by inverter 
(anti-islanding relays are open, due to problems with the grid). When 
anti-islanding relays are open, I have an issue of grounding the neutral 
conductor of output for homeloads. How can this grounding be achieved? Clause 
19.2 does not allow grounding inside the unit (or I have  understood it 
incorrectly and it only prohibits fixed connection) and clause 19.3 requires 
that output is grounded. Below is extract from the standard.
Any idea? I think it is the same issue as with UPS.

19.2 An inverter intended to be utility-interactive shall not have a 
direct/solid electrical connection between any output ac conductor and the 
enclosure.

19.3 Other than as specified in 19.2, each ac output circuit shall have a 
grounded conductor. The ac output circuit conductor to be grounded shall be as 
follows:
a) Single-phase, 2-wire - one conductor.
b) Single-phase, 3-wire - the neutral conductor.
c) Multiphase system having one wire common to all phases - the common 
conductor.
d) Multiphase system in which one phase is used as in item (b) - the neutral 
conductor.

19.4 The conductor specified in 19.3 is to be connected by a bonding jumper 
connected between the grounded conductor and:
a) The enclosure of a metal-enclosed unit, or
b) For a nonmetallic enclosed unit, the metal chassis that is bonded to the 
equipment grounding conductor or terminal. See 18.2.1.

Thank you for your support.

Best regards,
Bostjan

-

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This message is from the IEEE Product Safety Engineering Society emc-pstc 
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Re: [PSES] grounding of output of solar inverter

2016-02-16 Thread Brian O'Connell 
Also, should have noted to reference the NDs in UL62109-1, which further 
addresses below requirements, as stuff in North America is (finally) being 
harmonized at both building code and equipment standards levels.

See this:
http://publicaa.ansi.org/sites/apdl/Documents/Standards%20Action/2016-PDFs/SAV4704.pdf

Brian

-Original Message-
From: Brian O'Connell [mailto:oconne...@tamuracorp.com] 
Sent: Tuesday, February 16, 2016 9:28 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] grounding of output of solar inverter

Reference articles 250 and 690 of the NEC (NFPA70). Canada and Mexico code 
similar.

Brian

From: Boštjan Glavič [mailto:bostjan.gla...@siq.si] 
Sent: Monday, February 15, 2016 9:05 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] grounding of output of solar inverter

Dear experts,

Is anyone familiar with UL 1741? I am dealing with solar inverter for US 
market. Solar inverter can operate in utility interactive mode (feeding the 
grid) or in  a standalone mode where only homeloads are supplied by inverter 
(anti-islanding relays are open, due to problems with the grid). When 
anti-islanding relays are open, I have an issue of grounding the neutral 
conductor of output for homeloads. How can this grounding be achieved? Clause 
19.2 does not allow grounding inside the unit (or I have  understood it 
incorrectly and it only prohibits fixed connection) and clause 19.3 requires 
that output is grounded. Below is extract from the standard.
Any idea? I think it is the same issue as with UPS.

19.2 An inverter intended to be utility-interactive shall not have a 
direct/solid electrical connection between any output ac conductor and the 
enclosure.

19.3 Other than as specified in 19.2, each ac output circuit shall have a 
grounded conductor. The ac output circuit conductor to be grounded shall be as 
follows:
a) Single-phase, 2-wire - one conductor.
b) Single-phase, 3-wire - the neutral conductor.
c) Multiphase system having one wire common to all phases - the common 
conductor.
d) Multiphase system in which one phase is used as in item (b) - the neutral 
conductor.

19.4 The conductor specified in 19.3 is to be connected by a bonding jumper 
connected between the grounded conductor and:
a) The enclosure of a metal-enclosed unit, or
b) For a nonmetallic enclosed unit, the metal chassis that is bonded to the 
equipment grounding
conductor or terminal. See 18.2.1.

Thank you for your support.

Best regards,
Bostjan

-

This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail to 


All emc-pstc postings are archived and searchable on the web at:
http://www.ieee-pses.org/emc-pstc.html

Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

Website:  http://www.ieee-pses.org/
Instructions:  http://www.ieee-pses.org/list.html (including how to unsubscribe)
List rules: http://www.ieee-pses.org/listrules.html

For help, send mail to the list administrators:
Scott Douglas 
Mike Cantwell 

For policy questions, send mail to:
Jim Bacher:  
David Heald: 

-

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discussion list. To post a message to the list, send your e-mail to 


All emc-pstc postings are archived and searchable on the web at:
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Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

Website:  http://www.ieee-pses.org/
Instructions:  http://www.ieee-pses.org/list.html (including how to unsubscribe)
List rules: http://www.ieee-pses.org/listrules.html

For help, send mail to the list administrators:
Scott Douglas 
Mike Cantwell 

For policy questions, send mail to:
Jim Bacher:  
David Heald:

Re: [PSES] grounding of output of solar inverter

2016-02-16 Thread Brian O'Connell 
Reference articles 250 and 690 of the NEC (NFPA70). Canada and Mexico code 
similar.

Brian

From: Boštjan Glavič [mailto:bostjan.gla...@siq.si] 
Sent: Monday, February 15, 2016 9:05 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] grounding of output of solar inverter

Dear experts,

Is anyone familiar with UL 1741? I am dealing with solar inverter for US 
market. Solar inverter can operate in utility interactive mode (feeding the 
grid) or in  a standalone mode where only homeloads are supplied by inverter 
(anti-islanding relays are open, due to problems with the grid). When 
anti-islanding relays are open, I have an issue of grounding the neutral 
conductor of output for homeloads. How can this grounding be achieved? Clause 
19.2 does not allow grounding inside the unit (or I have  understood it 
incorrectly and it only prohibits fixed connection) and clause 19.3 requires 
that output is grounded. Below is extract from the standard.
Any idea? I think it is the same issue as with UPS.

19.2 An inverter intended to be utility-interactive shall not have a 
direct/solid electrical connection between any output ac conductor and the 
enclosure.

19.3 Other than as specified in 19.2, each ac output circuit shall have a 
grounded conductor. The ac output circuit conductor to be grounded shall be as 
follows:
a) Single-phase, 2-wire - one conductor.
b) Single-phase, 3-wire - the neutral conductor.
c) Multiphase system having one wire common to all phases - the common 
conductor.
d) Multiphase system in which one phase is used as in item (b) - the neutral 
conductor.

19.4 The conductor specified in 19.3 is to be connected by a bonding jumper 
connected between the grounded conductor and:
a) The enclosure of a metal-enclosed unit, or
b) For a nonmetallic enclosed unit, the metal chassis that is bonded to the 
equipment grounding
conductor or terminal. See 18.2.1.

Thank you for your support.

Best regards,
Bostjan

-

This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail to 


All emc-pstc postings are archived and searchable on the web at:
http://www.ieee-pses.org/emc-pstc.html

Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

Website:  http://www.ieee-pses.org/
Instructions:  http://www.ieee-pses.org/list.html (including how to unsubscribe)
List rules: http://www.ieee-pses.org/listrules.html

For help, send mail to the list administrators:
Scott Douglas 
Mike Cantwell 

For policy questions, send mail to:
Jim Bacher:  
David Heald: