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b) Earthed DC MAINS SUPPLIES; n# j5 L- d2 s T0 {( Y
If a DC MAINS SUPPLY is connected to protective earth and is entirely within a single building,
r7 p) v0 B: |( D. ithe MAINS TRANSIENT VOLTAGE shall be assumed to be 71 V peak. If this connection is within; O. ~; E0 N e7 I% C. f
the EUT, it shall be in accordance with 2.6.1 d).& [2 D8 k$ z( B2 c+ \
NOTE 3 The connection to protective earth can be at the source of the DC MAINS SUPPLY or at the equipment: q; w: q# A2 ~3 G1 u
location, or both (see ITU-T Recommendation K.27)., ^8 L5 P8 {: W4 o, n
c) Unearthed DC MAINS SUPPLIES
7 }6 Q1 k6 ~: S ?3 y6 @If a DC MAINS SUPPLY is not earthed and located as in b) above, the MAINS TRANSIENT VOLTAGE3 `3 t* p/ K2 N8 }
shall be assumed to be equal to the MAINS TRANSIENT VOLTAGE in the AC MAINS SUPPLY from
2 N6 b3 K" K% D* w* N( z7 Xwhich the DC MAINS SUPPLY is derived., p1 Q% R1 _! O8 o) a
4 z0 p) ?. c9 N+ F你可以先归类,看属于B,还是C |
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