Three phase load with neutral balancing

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mustafa

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How to check or test if the load connected is balanced or not noting that i have three phase loads(400V star connection)like hotplate ,boiler,three phase socket
which is connected to 3 pole RCD, this may affect RCD no of poles selected prior proper operation?
 
mustafa said:
How to check or test if the load connected is balanced or not noting that i have three phase loads(400V star connection)like hotplate ,boiler,three phase socket
which is connected to 3 pole RCD, this may affect RCD no of poles selected prior proper operation?
Click to expand...
If any of the loads are connected from one hot lead to neutral, then the RCD must sense the three phase leads and the neutral, even though it may only interrupt the three phase leads when it trips.
When you have a multiwire circuit which includes a shared neutral you cannot use separate RCDs on individual phases.
 
kwired said:
Are there line to neutral loads being served or just straight three phase loads?
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It is three lines+neutral for (hotplate,boiler and three phase service receptacle at roof level) line to neutral may be for auxiliary or control circuits or heaters inside theses loads
 
please note that i have this case at site
Three phase load with neutral connection but the RCD at panel side is three pole only what is expected from this connection?
 
mustafa said:
please note that i have this case at site
Three phase load with neutral connection but the RCD at panel side is three pole only what is expected from this connection?
Click to expand...
RCD's there are similar to GFCI's here. They operate on a net-zero EMF principle. Deviation beyond a predetermined threshold from a net-zero condition trips the unit. As mentioned earlier, your unit's sensing must include all circuit conductors, including the neutral. Yours seems to be only for a 3-wire circuit, not a 4-wire circuit.
 
mustafa said:
please note that i have this case at site
Three phase load with neutral connection but the RCD at panel side is three pole only what is expected from this connection?
Click to expand...

My expectation is any load to neutral over the trip threshold (probably 30mA or so) will trip the unit. Balancing the neutral load would keep it from tripping but 30mA is too low of a threshold to be able to do this for the most part.
 
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