United States Nuclear Regulatory Commission - Protecting People and the Environment

ACCESSION #: 9505300156

MKW POWER SYSTEMS, Inc.

April 24, 1995

Thomas Murley
Director
Office of Nuclear Reactor Regulation
11555 Rockville Pike
Rockville, MD 20852

Reference:     Report No. 10CFR21-0071

Subject:       Reportable defect with Square D type KPD relay

Dear Mr. Murley:

MKW Power Systems was notified on 2/23/95 by Wisconsin Electric - Point
Beach about a contact failure of a Square D type KPD this relay used in
their diesel generator control panel.  Our review of this subject is not
yet complete.  We estimate a completion date of 5/8/95.

An interim report is attached which describes the condition.

Yours very truly,

MKW POWER SYSTEMS, INC.

Michael Nuding
General Manager - Quality Assurance

MN:dg

Enclosure

    Post Office Box 1928 o Rocky Mount, North Carolina 27802-1928 o
    Phone: (919) 977-2720  TWX: (510) 929-0725 o FAX: (919) 446-3830

MKW POWER SYSTEMS, Inc.

                                             Report No. 10CFR21-0071I
                                             April 24, 1995

                             INTERIM REPORT

                      10CFR21 REPORTING OF DEFECTS
                           AND NON-COMPLIANCE

COMPONENT:     Square D Class 8501, Type KPD relay

SYSTEM:        EMD Diesel Generator control systems

CONCLUSION:    To be determined

PREPARED BY:                                      DATE:
               Donald D. Galeazzi
               Engineering Manager

APPROVED BY:                                      DATE:
               Michael Nuding
               General Manager, Quality Assurance

    Post Office Box 1928 o Rocky Mount, North Carolina 27802-1928 o
    Phone: (919) 977-2720  TWX: (510) 929-0725 o FAX: (919) 446-3830

                                             REPORT NO. 10CFR21-0071I
                                             PAGE: 1 OF 4

SUMMARY

Recent information has revealed a change in published DC contact ratings
of Square D type KPD relays .  These relays are used by MKW Power Systems
in diesel generator 125 VDC control circuits.

MKW Power Systems received notification on 2/23/95 from Wisconsin
Electric - Point Beach about a contact failure of the BTR (breaker trip
relay) within the diesel generator control panel.  The contact was wired
out for customer use; Wisconsin Electric utilized the relay contact to
trip their 86 lockout relay.  Investigation by Wisconsin Electric
revealed that their circuit required approximately 1.3 amps @ 125 VDC.
This lead Wisconsin Electric to verify the contact ratings of the BTR
relay (Square D class 8501, type KPD-13).  Square D indicated that the
KPD-13 relay did not have any DC ratings.  MKW Power Systems performed
further investigation with Square D which revealed that Square D had
recently corrected their catalog to remove the DC ratings.  Previous
issues of the Square D Digest provided the following contact ratings (see
Exhibit 2):

     1985:     10A continuous, make/break 60 VA @ 125 VDC.
     1990:     10A continuous @ 6-120 VDC.
     1992:     no DC contact ratings.
     1994:     no DC contact ratings.

According to Square D, the above changes in contact ratings were due to
catalog errors; not due to design changes of the KPD-13 relay.

MKW Power Systems informed Square D that they have been utilizing the
KPD-13 relays in 125 VDC circuits for more than twenty years with
successful results and therefore the relays have demonstrated their
capability to handle DC loads.  Square D contacted their supplier and
provided the following ratings (see Exhibit 1):

     10A continuous, make/break 50 VA (.4A) @ 125 VDC.

Some KPD contacts within the MKW Power Systems' control panels are wired-

out  to terminals for "customer's use".  These contacts are used for
applications such as: D/G circuit breaker close, D/G circuit break trip,
86 relay trip, etc..  The above contact make/break ratings are less than
the original ratings of 60 VA and therefore users should be notified of
this deviation.

COMPONENTS

Square D class 8501, type KPD relays.

     KPD-13 (3 pole version)
     KPD-12 (2 pole version)

                                        REPORT NO. 10CFR21-0071I
                                        PAGE: 2 OF 4

CUSTOMERS AFFECTED

To be determined.

DEFECT

The defect has been identified as a change in the DC make/break contact
rating of the Square D type KPD relay.  Square D's most recent
publications show the relay as not having any DC contact ratings, but
they have verified with their relay supplier that the relay can
make/break 0.4 amps (50 VA) and carry 10 amps continuously @ 125 VDC.
This make/break rating is less than the originally published rating of 60
VA @ 125 VDC.  MKW Power Systems has been utilizing the KPD relay in
their 125 VDC control circuitry for more than twenty (20) years.  During
this time period, contact failures due to excessive current have not been
a problem.  All customers (except FP&L - Turkey Point and Wisconsin
Electric - Point Beach) have at least ten (10) years of operating
experience.  Because of this operating experience MKW Power Systems does
not believe that the described change in contact ratings will affect the
operability of its diesel generators in nuclear safety related service.
Circuitry for FP&L and Wisconsin Electric control panels is being
reviewed to determine if loads beyond the 50 VA contact rating exist.

CORRECTIVE ACTION

Users should review their circuitry which utilize "customer use" KPD
relay contacts and verify that the new contact ratings are not exceeded.

For Wisconsin Electric-Point Beach relays SDRX2 and BTR have been
identified as being utilized in circuitry which exceeds the 50 VA contact

rating.  Wisconsin Electric has replaced these relays with ones having
adequate contact ratings.

                                             REPORT NO. 10CFR21-0071I
                                             PAGE: 3 OF 4

                                EXHIBIT 1
                                (1 pages)

                      SQUARE D TO MKW POWER SYSTEMS

                        KPD RELAY CONTACT RATINGS

                          FACSIMILE TRANSMITTAL

          SQUARE D COMPANY
          AUTOMATION AND CONTROL BUSINESS
          HIGHWAY 64 EAST, KNIGHTDALE, NC 27545

          NUMBER OF PAGES INCLUDING THIS PAGE: 1
          IF YOU HAVE NOT RECEIVED ALL PAGES CALL: 919-266-8298.

DATE:     March 17, 1995

  TO:     Michael Nuding                     FAX NO. 919 / 446 - 6112
          MKW Power Systems

FROM:     John Nussbaum - Raleigh Marketing  FAX NO. 919 / 266 - 8393

SUBJECT:  8501 KPD13 Relays
          DC Contact Ratings

          The 8501 KPD13 relay doesn't have any UL approved DC contact
          ratings.  The information published in our 1990 Digest was
          incorrect.  The information shown in our current Digest is
          correct.

          Our supplier has done some in home testing and they say it will
          make and break 10 amp, at 28 VDC and 0.4 amps, at 125 VDC.  The
          contacts will continuously carry, but not make or break, 10
          amps, at 125 VDC.  There is no testing available to support a
          60 VA rating.

          I hope this information helps you.  If I can be of any further
          help, please call me at (919) 266 - 8298.

          Regards,

Page 1

                                             REPORT NO. 10CFR21-0071I
                                             PAGE: 4 OF 4

                                EXHIBIT 2
                                (4 pages)

                         SQUARE D CATALOG PAGES

           KPD RELAY CONTACT RATINGS (1985, 1990, 1992, 1994)

Figure "GENERAL PURPOSE CONTROL RELAYS, TYPE K, CLASS 8501" omitted.

Figure "LOGIC PRODUCTS, GENERAL PURPOSE RELAYS, TYPE K -- PLUG-IN, CLASS
8501" omitted.

Figure "General Purpose Relays, Type K -- Plug-in Relay, Application
Data, Dimensions, Wiring Diagrams, Class 8501", 2 pages, omitted.

MKW POWER SYSTEMS, Inc.

301 South Church Street
Station Square, Suite 100
Rocky Mount, NC 27804
Phone: (919) 977-2720
TWX: (510) 929-0725
FAX: (919) 446-1134

                                 TELEFAX

DATE:          April 24, 1995

COMPANY:       Office of Nuclear Reactor Regulation

FAX NUMBER:    301-415-1887

ATTENTION:     Thomas Murley

REFERENCE:     Interim Report #10CFR21-0071I

FROM:          Michael Nuding

IF YOU DO NOT RECEIVE ALL PAGES LISTED, PLEASE CALL EXTENSION 253.

PAGES (INCLUDING COVER SHEET): 12

Dear Sir:

Following this cover is a copy of an interim report for the Square D type
KPD relay.

Should you have questions, please let us know.

Sincerely,

MKW POWER SYSTEMS, INC.

Michael Nuding
General Manager-Quality Assurance

*** END OF DOCUMENT ***

Page Last Reviewed/Updated Thursday, March 29, 2012