We have 3 phase power supply in my home which is used to power single phase 240V 50 hz appliances with common neutral. (Diagram in the link at the bottom)
The only protection we have as of now are MCBs down each phase. But we recently faced a big problem.
Few days back, the neutral wire of the distribution line outside our home broke and fell on the ground. This happened probably due to impoper maintenance by company, summer heat and heavy load. Whatever may be the reason, this fault damaged our wasing machine, air condtioners, water filter, laptop charger and other appliences. This was a big setback for us. So, I am trying to figure out
- Why this damage happened and
- What can be done to prevent this in future? Are there some device which can be installed to protect the home circuit?
I researched a bit around web and it seems this problem is called neutral fault. This decreses the volatage across some loads and increases across others. High voltage can reach up to 380 to 400 V.
Solution I have found so far is to install a RCBO-4P at input from main lines. So I want to know will this solution work? Will a 4 pole residual current circuit breaker with over load protection trip, if the neutral input is disconnected?
Thanks a lot.
Wikipedia says, "To provide some protection with an interrupted neutral, some RCDs and RCBOs are equipped with an auxiliary connection wire that must be connected to the earth busbar of the distribution board. This either enables the device to detect the missing neutral of the supply, causing the device to trip, or provides an alternative supply path for the tripping circuitry, enabling it to continue to function normally in the absence of the supply neutral."