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TELECOM POSITIVE GROUNDING

TELECOM POSITIVE GROUNDING

TELECOM POSITIVE GROUNDING

(OP)
WHAT IS THE REASON THE TELECOM INDUSTRY USES NEGATIVE 48V, POSITIVE GROUND?

RE: TELECOM POSITIVE GROUNDING

Cool site, busbar.

I was interested to see what it had to say on this.  No luck with the search engine, but the FAQ page linked to off the home page had the answer.

RE: TELECOM POSITIVE GROUNDING


peebee, although it has nothing to do directly with grounding, polarity in protective-relay trip circuits seems to have a slightly conflicting rationale.

From http://www.pes-psrc.org/k/rlytrckt.zip…  In order to minimize the effect of corrosion, relay coils should be permanently connected to the negative bus in dc control schemes.  If moisture is present and the coil is directly connected to the positive bus, electrolytic corrosion may occur, causing the coil to become open-circuited and preventing the relay from operating.
  

RE: TELECOM POSITIVE GROUNDING

Interesting.  This would seem to expain too why cars have a negative ground.  Strange that the same phenomenon would dictate different grounding arrangements.  

You've made my head hurt once again busbar.

RE: TELECOM POSITIVE GROUNDING


peebee — if severe pain persists, combined shots of intramuscular Stadol and Toradol can be quite effective.  
  

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