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b) Earthed DC MAINS SUPPLIES- F$ y' d4 ~1 B
If a DC MAINS SUPPLY is connected to protective earth and is entirely within a single building,
. `7 p$ V. }$ V$ ]4 D0 kthe MAINS TRANSIENT VOLTAGE shall be assumed to be 71 V peak. If this connection is within
% X$ R8 g9 V5 E8 kthe EUT, it shall be in accordance with 2.6.1 d).' ?& J6 j9 }& E
NOTE 3 The connection to protective earth can be at the source of the DC MAINS SUPPLY or at the equipment- p0 q7 I) p% X k7 Z
location, or both (see ITU-T Recommendation K.27).
( ? U8 S/ T3 H. o. Gc) Unearthed DC MAINS SUPPLIES
$ e7 c9 R0 a' T9 q6 U# ]0 MIf a DC MAINS SUPPLY is not earthed and located as in b) above, the MAINS TRANSIENT VOLTAGE6 a! ^; r" T0 ]1 b
shall be assumed to be equal to the MAINS TRANSIENT VOLTAGE in the AC MAINS SUPPLY from. F2 ^' E% m' X
which the DC MAINS SUPPLY is derived.. t2 ^- K( Q; W; o( Z- r3 L# m& b
! t6 J. X1 V; y( F+ S- c3 I& s你可以先归类,看属于B,还是C |
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