Common use of Existing Secured Indebtedness Clause in Contracts

Existing Secured Indebtedness. First Mortgage Bonds Outstanding under Mortgage and Deed of Trust Dated as of June 1, 1939, as Modified by Supplemental Indentures Thereto SUPPLEMENTAL INDENTURE DATED AS OF SERIES PRINCIPAL AMOUNT ISSUED PRINCIPAL AMOUNT OUTSTANDING NO. DESIGNATION Twenty-Sixth April 1, 1993 24 Secured Medium-Term Notes, Series A ($250,000,000 authorized) $250,000,000 $13,500,000 Thirty-fifth December 1, 2004 33 Collateral Series 2004A $88,850,000 $25,000,000 Thirty-ninth November 1, 2005 39 6.25% Series due 2035 $100,000,000 $50,000,000 $100,000,000 $50,000,000 Forty-first December 1, 2006 41 5.70% Series due 2037 $150,000,000 $150,000,000 Forty-eighth December 1, 2010 48 Collateral Series 2010A $66,700,000 $66,700,000 Forty-eighth December 1, 2010 49 Collateral Series 2010B $17,000,000 $17,000,000 Forty-ninth December 1, 2010 51 5.55% Series due 2040 $35,000,000 $35,000,000 Fifty-third December 1, 2011 54 4.45% Series due 2041 $85,000,000 $85,000,000 Fifty-fourth November 1, 2012 55 4.23% Series due 2047 $80,000,000 $80,000,000 Fifty-seventh December 1, 2014 58 4.11% Series due 2044 $60,000,000 $60,000,000 Fifty-eighth December 1, 2015 59 4.37% Series due 2045 $100,000,000 $100,000,000 Fifty-ninth December 1, 2016 60 3.54% Series due 2051 $175,000,000 $175,000,000 Sixtieth December 1, 2017 61 3.91% Series due 2047 $90,000,000 $90,000,000 Sixty-first May 1, 2018 62 4.35% Series due 2048 $375,000,000 $375,000,000 Sixty-second November 1, 2019 63 3.43% Series due 2049 $180,000,000 $180,000,000 Sixty-third June 1, 2020 64 Collateral Series 2020A due 2026 $400,000,000 $400,000,000 Sixty-fourth September 1, 2020 65 3.07% Series due 2050 $165,000,000 $165,000,000 Sixty-fifth September 1, 2021 66 2.90% Series due 2051 $140,000,000 $140,000,000 Sixty-sixth March 17, 2022 67 4.00% Series due 2052 $400,000,000 $400,000,000 Aggregate principal amount of First Mortgage Bonds outstanding through and including the Sixty-sixth Supplemental Indenture = $2,707,200,000.

Existing Secured Indebtedness. First Mortgage Bonds Outstanding under Mortgage and Deed of Trust Dated as of June 1, 1939, as Modified by Supplemental Indentures Thereto SUPPLEMENTAL INDENTURE DATED AS OF SERIES PRINCIPAL AMOUNT PRINCIPALAMOUNT ISSUED PRINCIPAL AMOUNT OUTSTANDING PRINCIPALAMOUNTOUTSTANDING NO. DESIGNATION Twenty-Sixth April 1, 1993 24 Secured Medium-Term Notes, Series A ($250,000,000 authorized) $250,000,000 $13,500,000 36,000,000 Thirty-fourth November 1, 2004 32 5.45% Series due 2019 $90,000,000 $90,000,000 Thirty-fifth December 1, 2004 33 Collateral Series 2004A $88,850,000 $25,000,000 Thirty-ninth November 1, 2005 39 6.25% Series due 2035 $100,000,000 100,000,000$50,000,000 $50,000,000 $100,000,000 $50,000,000 100,000,000$50,000,000 Forty-first December 1, 2006 41 5.70% Series due 2037 $150,000,000 $150,000,000 Forty-second April 1, 2008 42 5.95% Series due 2018 $250,000,000 $250,000,000 Forty-sixth September 1, 2009 46 5.125% Series due 2022 $250,000,000 $250,000,000 Forty-eighth December 1, 2010 48 Collateral Series 2010A $66,700,000 $66,700,000 Forty-eighth December 1, 2010 49 Collateral Series 2010B $17,000,000 $17,000,000 Forty-ninth December 1, 2010 50 3.89% Series due 2020 $52,000,000 $52,000,000 Forty-ninth December 1, 2010 51 5.55% Series due 2040 $35,000,000 $35,000,000 Fiftieth December 1, 2010 52 1.68% Series due 2013 $50,000,000 $50,000,000 Fifty-first February 1, 2011 53 Collateral Series 2011A $400,000,000 $400,000,000 Fifty-third December 1, 2011 54 4.45% Series due 2041 $85,000,000 $85,000,000 Fifty-fourth November 1, 2012 55 4.23% Series due 2047 $80,000,000 $80,000,000 Fifty-seventh December 1, 2014 58 4.11% Series due 2044 $60,000,000 $60,000,000 Fifty-eighth December 1, 2015 59 4.37% Series due 2045 $100,000,000 $100,000,000 Fifty-ninth December 1, 2016 60 3.54% Series due 2051 $175,000,000 $175,000,000 Sixtieth December 1, 2017 61 3.91% Series due 2047 $90,000,000 $90,000,000 Sixty-first May 1, 2018 62 4.35% Series due 2048 $375,000,000 $375,000,000 Sixty-second November 1, 2019 63 3.43% Series due 2049 $180,000,000 $180,000,000 Sixty-third June 1, 2020 64 Collateral Series 2020A due 2026 $400,000,000 $400,000,000 Sixty-fourth September 1, 2020 65 3.07% Series due 2050 $165,000,000 $165,000,000 Sixty-fifth September 1, 2021 66 2.90% Series due 2051 $140,000,000 $140,000,000 Sixty-sixth March 17, 2022 67 4.00% Series due 2052 $400,000,000 $400,000,000 Aggregate principal amount of First Mortgage Bonds outstanding through and including the Sixty-sixth Supplemental Indenture = $2,707,200,000.80,000,000

Existing Secured Indebtedness. First Mortgage Bonds Outstanding under Mortgage and Deed of Trust Dated as of June 1, 1939, as Modified by Supplemental Indentures Thereto SUPPLEMENTAL INDENTURE DATED AS OF SERIES PRINCIPAL AMOUNT ISSUED PRINCIPAL AMOUNT OUTSTANDING NO. DESIGNATION Twenty-Sixth April 1, 1993 24 Secured Medium-Term Notes, Series A ($250,000,000 authorized) $250,000,000 $13,500,000 43,000,000 Thirty-fourth November 1, 2004 32 5.45% Series due 2019 $90,000,000 $90,000,000 Thirty-fifth December 1, 2004 33 Collateral Series 2004A $88,850,000 $25,000,000 Thirty-ninth November 1, 2005 39 6.25% Series due 2035 $100,000,000 $50,000,000 $100,000,000 $50,000,000 Fortieth April 1, 2006 40 Collateral Series due 2011 $320,000,000 $320,000,0001 Forty-first December 1, 2006 41 5.70% Series due 2037 $150,000,000 $150,000,000 Forty-second April 1, 2008 42 5.95% Series due 2018 $250,000,000 $250,000,000 Forty-sixth September 1, 2009 46 5.125% Series due 2022 $250,000,000 $250,000,000 Forty-seventh November 1, 2009 47 Collateral Series 2009A $75,000,000 $75,000,0001 Forty-eighth December 1, 2010 48 Collateral Series 2010A $66,700,000 $66,700,000 Forty-eighth December 1, 2010 49 Collateral Series 2010B $17,000,000 $17,000,000 Forty-ninth December 1, 2010 50 3.89% Series due 2020 $52,000,000 $52,000,000 Forty-ninth December 1, 2010 51 5.55% Series due 2040 $35,000,000 $35,000,000 Fifty-third Fiftieth December 1, 2011 54 4.452010 52 1.68% Series due 2041 2013 $85,000,000 50,000,000 $85,000,000 Fifty-fourth November 1, 2012 55 4.23% Series due 2047 $80,000,000 $80,000,000 Fifty-seventh December 1, 2014 58 4.11% Series due 2044 $60,000,000 $60,000,000 Fifty-eighth December 1, 2015 59 4.37% Series due 2045 $100,000,000 $100,000,000 Fifty-ninth December 1, 2016 60 3.54% Series due 2051 $175,000,000 $175,000,000 Sixtieth December 1, 2017 61 3.91% Series due 2047 $90,000,000 $90,000,000 Sixty-first May 1, 2018 62 4.35% Series due 2048 $375,000,000 $375,000,000 Sixty-second November 1, 2019 63 3.43% Series due 2049 $180,000,000 $180,000,000 Sixty-third June 1, 2020 64 Collateral Series 2020A due 2026 $400,000,000 $400,000,000 Sixty-fourth September 1, 2020 65 3.07% Series due 2050 $165,000,000 $165,000,000 Sixty-fifth September 1, 2021 66 2.90% Series due 2051 $140,000,000 $140,000,000 Sixty-sixth March 17, 2022 67 4.00% Series due 2052 $400,000,000 $400,000,000 50,000,000 Aggregate principal amount of First Mortgage Bonds outstanding through and including the Sixty-sixth Fiftieth Supplemental Indenture (but excluding the Fifty-first Supplemental Indenture) = $2,707,200,0001,573,700,000.