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11kV/400V TX with no LV protection

amlec2021

I am working on a project where we have been asked to install a new LV cable from the outgoing side of a transformer to a new Panel board however the outgoing side of the transformer does not have any protection. We have raised this with the client however they have advised this is not an issue. I am looking for some guidance to back up our argument that the LV cable does not have any protection.

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  • This might be acceptable.

    Short conductors connecting a transformer to fuses or MCCBs are permitted without any short circuit or overload protection.

    Also overload protection can be omitted if the characteristics of the load prevent overload. For example if the cable is good for 300 amps, but the load can not exceed 300 amps, then that is probably acceptable. Short circuit protection would still be required, but that MIGHT be provided by the fuses or circuit breaker on the 11 kv input to the transformer.

  • in reply to broadgage

    Thanks for the reply. I understand that overload protection might not be required if there is no chance of overload but where is it stated that short circuit protection is not required if connecting short length of cable and what constitutes as short length.

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  • in reply to broadgage

    Thanks for the reply. I understand that overload protection might not be required if there is no chance of overload but where is it stated that short circuit protection is not required if connecting short length of cable and what constitutes as short length.

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