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I have a customer with a farm who has a barn containing a large 3 phase generator which powers various equiptment at that location. A single phase from this also supplies a ring main and lighting radial for the building. That part of the setup has a generator changeover switch so that the sockets and lights can also be powered by the main site supply without starting the generator. This mains supply comes via a 50m cable from the farmhouse.
Due to the rural location the customer often has power outages and would like to be able to power the house from the generator. The most vanilla way to do this of course would be to run another armored cable from the farmhouse to the barn to supply directly from the single-phase output side of the barn change-over to a changeover switch at the properties meter tails. However the cost of running the cable from the house to the barn would be significant, and the customer does not understand he cannot reuse the existing cable.
The reason is of couse that with switch-gear at both ends of the barn-house cable there would be nothing to prevent switch configurations that left the mains directly connected to the generator.
Has anyone encountered this before and know of a standard approach. To my mind there are a few options, both centered around the design that there must exist some physical thing that can only be at one end of the cable or the other.
- dual pole 100amp key switch isolators at locations in each building, with a single key that cannot be removed in the on position
RISK ASSESSMENT: customer could duplicate key
RISK mitigation: note attached to the key prohibiting this, with reasoning.
- add plug and socket configurations at each end of the cable, with the same gender on each end of the cable (probably female). provide a gender changer which is used to
make one end, and only one end, of the cable become the power-in side.
RISK: The end of the tail that connects to the cable will be live and male when setting up.
customer could make up their own tail.
Risk migigation: User has to be considered skilled/educated to the risk, supplies can be rcd protected.
Warning against additional tail would need to be displayed.
- add two supplier cut out housings (one to live and one to phase) to meter tails before consumer unit. Add matching cut outs that bridge the barn generator-changeover switch.
supply two non-fused cutout links (the red sort) which must be moved to whichever location is to be the supply.
RISK: customer could purchase additional red links. A single link could be moved. links could be removed/placed under load causing arcing.
RISK migigation: warning notice. Possibly connect the two links to each other via a tether, so both have to move location.
Due to the rural location the customer often has power outages and would like to be able to power the house from the generator. The most vanilla way to do this of course would be to run another armored cable from the farmhouse to the barn to supply directly from the single-phase output side of the barn change-over to a changeover switch at the properties meter tails. However the cost of running the cable from the house to the barn would be significant, and the customer does not understand he cannot reuse the existing cable.
The reason is of couse that with switch-gear at both ends of the barn-house cable there would be nothing to prevent switch configurations that left the mains directly connected to the generator.
Has anyone encountered this before and know of a standard approach. To my mind there are a few options, both centered around the design that there must exist some physical thing that can only be at one end of the cable or the other.
- dual pole 100amp key switch isolators at locations in each building, with a single key that cannot be removed in the on position
RISK ASSESSMENT: customer could duplicate key
RISK mitigation: note attached to the key prohibiting this, with reasoning.
- add plug and socket configurations at each end of the cable, with the same gender on each end of the cable (probably female). provide a gender changer which is used to
make one end, and only one end, of the cable become the power-in side.
RISK: The end of the tail that connects to the cable will be live and male when setting up.
customer could make up their own tail.
Risk migigation: User has to be considered skilled/educated to the risk, supplies can be rcd protected.
Warning against additional tail would need to be displayed.
- add two supplier cut out housings (one to live and one to phase) to meter tails before consumer unit. Add matching cut outs that bridge the barn generator-changeover switch.
supply two non-fused cutout links (the red sort) which must be moved to whichever location is to be the supply.
RISK: customer could purchase additional red links. A single link could be moved. links could be removed/placed under load causing arcing.
RISK migigation: warning notice. Possibly connect the two links to each other via a tether, so both have to move location.
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