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3 pole contractor fed from 3 separate MCBs

Hi,

Any issue having 3x single pole (single phase) MCBs, switched by a 3 pole contactor, feeding 3 different runs of lights? The 3 circuits will be on different phases. There will be a separate neutral for each circuit. 

Each pole of the contactor is rated for the connected load and the number of lights it’s switching. 

Generally contactors are fed from an interlinked 3 pole MCB, however for this setup we need to use single pole MCBs to prevent 1 circuit tripping the other 2 runs of lights if there was a fault of the need to isolate one of the circuits. 

Don’t foresee it as an issue as long as the contactor is labelled as having multiple points of isolation. To me this is no different than a big grid switch, or a contactor fed from fuses. 

Anyone think otherwise?

Thanks. 

Parents
  • Probably OK unless any part of it is in a situation or installation which requires all live conductors - line(s) and neutral - to be disconnected for isolation, because Reg 531.1 states (1st para) that devices for ADS shall be suitable for isolation.

    Probably OK for most TN and TT systems, provided in TT at least there is a common means of isolation disconnecting all poles (including Neutral), but check special locations and other types of supply if applicable.

  • Thanks 

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