Clause 13.1 from UL 1741 and 690.17 from the 2011 NEC both require that disconnects consist of a manually operated switch or circuit breaker (this part of 2014 NEC has been modified). It may be a bit of a judgment call as to whether a contactor can meet the intent of these requirements. As least some folks have judged that it can on the PV side, since there are combiner boxes on the market now that use a contactor instead of a traditional disconnect switch or circuit breaker. Here is one example with a photo showing the Gigavac contactor inside with a manually operated switch in the coil circuit:
http://www.solarbos.com/products/combiner-boxes/arc-fault-combiner-boxes This combiner box was listed to UL 1741 by ETL. It is important not to touch a circuit isolated this way without first verifying with a meter that it is safe. This type of contactor is typically certified to UL 508 for the USA market though this should be moving to the UL 60947 standards going forward. I am not aware of any application that currently uses this sort of arrangement on the AC side. There are additional requirements for the AC side disconnect since this is the PV system disconnect from the grid, often as part of interconnect requirements imposed by utilities. The Canadian code, 84-024, requires a visible blade arrangement for verification of disconnection if required by the supply authority. Utilities often require the visible blade. Scott Aldous Compliance Manager/Engineering Lab Manager AE Solar Energy +1.970.492.2065 Direct +1.970.407.5872 Fax +1.541.312.3832 Main [email protected] 1625 Sharp Point Drive Fort Collins, CO 80525 www.advanced-energy.com/solarenergy -----Original Message----- From: Boštjan Glavič [mailto:[email protected]] Sent: Thursday, March 13, 2014 2:01 AM To: [email protected] Subject: [PSES] use of AC contactor in PV application in US/CAN Dear Experts, Is anyone familiar if it is allowed to use a contactor instead of circuit breaker in PV application to disconnect inverter from the grid? NEC in Article 690 does not specify it precisely. What standard needs to comply this contactor? Best regards, Boštjan Glavič Safety and Electromagnetics Laboratory of Electronic Engineering Head of Laboratory SIQ, Tržaška cesta 2 SI-1000 Ljubljana, Slovenia T: + 386 (0)1 47 78 265 F: + 386 (0)1 47 78 444 E-Mail: [email protected] - ---------------------------------------------------------------- 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 <[email protected]> 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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]> This message, including any attachments, may contain information that is confidential and proprietary information of Advanced Energy Industries, Inc. The dissemination, distribution, use or copying of this message or any of its attachments is strictly prohibited without the express written consent of Advanced Energy Industries, Inc. - ---------------------------------------------------------------- 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 <[email protected]> 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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
