24v supplies 1

[bigheadted]

assuming that all the 24v powersupplies in my system have neutrals tied to earth. what are the problems asssociated with using a neutral of one power supply with the live fom another. (the live is passed from one panel to the next in a loop of switches but the neutral is not) current rating of the connectors and cables is not a problem so is this bad working practice if so why?

 

[itsmoked]

Your question is unclear... What kind of 24V supplies? DC?

Neutral/live? Source side? Output side? I have about a dozen answers but not enough to give you a correct one!

Describe specifically your in-question set up.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[bigheadted]

sorry to hasty again
24vdc supply to an estop loop consisting of both normal stop buttons and contacts from the stop relays of remote units that have their own 24v dc power supplies.
i wish to put indicators along the estop loop to show where the 24v is broken,(this is a hardware stop loop that consists of about 100 contacts) obviously the live feed is the loop itself but my question is reguarding the neutral.
if the 24v is supplied from a one panel can i use the neutral from a separate 24v supply in a remote panel as the return path provided both the neutrals are tied to earth
i suppose i am also asking a more general question about the problems associated with mixing neutrals
many thanks
bigheadted

 

[itsmoked]

Ok much better and I see a problem with terms.

Nuetral is used to refer to:

1) The wire in a 120Vac circuit pair that is somewhere tied to an earth ground.

or

2) The same wire in a WYE 3 phase system.

The return for a 24Vdc system is called just that, "The 24V return".

Now then your question is, "Can you use any of the several 24Vdc returns spread about your system?".

Answer: I would not! While the many 24Vdc supplies in your system may all have their "returns" tied to earth grounds I would not consider them to be common! The 24Vdc eswitch loop should be just a single supply feeding the entire loop with the 24Vdc return being the "return" pin on the same 24Vdc supply. Anything else can cause myriad strange problems and may end up utilizing dirt or other AC power carrying conductors for a return path. A very poor and possibly even dangerous situation.



Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com