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Installing AWA in Trefoil

gibb01

Hi All,

We have a project installing a 630A Panel board from an LV panel board within the same room.  Due to space constraints we no longer think the 300mm SWA we were looking to install is going to be physically feasible.  So we've been looking at running 300mm AWA's in Trefoil instead. It's a short run of around 13m & the panel board is going to contain a mixture of different loads.

We're obviously using the Aluminum glands & terminating into an Aluminum plate either end, however not having had to install cables in trefoil before - I'm not sure if there is anything else we need to be mindful about. 

It's being installed on a 450mm ladder & I've checked within table 4C5 for spacing factors. I'm unsure if the neutral should be installed as close as possible to the trefoil? It's also been mentioned that Quad cleats are available to include the Neutral, Lastly it's been mentioned about potential single point bonding of the conductors - again something I've never had to do before.

I will be looking to get a design carried out, I just wondered if anyone had advice as it's not something we've had the need to carry out beforehand - So unsure whether there any pros / cons of doing this way as opposed to a standard 4 core SWA (Other than the physical impracticalities!)

Many thanks in advance. 

Tim

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  • 0

    4 core SWA of that size is almost unmanageable in a confined space, it is more applicable to burial. Or to long runs cleated along a structure.

    Single core AWA is commonly used for this sort of application and is bit better to handle. If reliance is being placed upon the aluminium armouring for earthing, then it needs connecting at both ends. Single point bonding  can give slightly higher current carrying capacity on long runs, but is insignificant on a short length as is being proposed.

    When terminating large single core cables, beware eddy currents in ferrous metals ! Aluminium is fine, but double check that this is actually used and NOT STEEL.

    A large bonding conductor is probably required between the aluminium gland plate and the main switch-gear enclosure. Reliance on the fixing bolts is unwise at this sort of current.

    I would use cleats that support all four cables,.

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  • 0

    4 core SWA of that size is almost unmanageable in a confined space, it is more applicable to burial. Or to long runs cleated along a structure.

    Single core AWA is commonly used for this sort of application and is bit better to handle. If reliance is being placed upon the aluminium armouring for earthing, then it needs connecting at both ends. Single point bonding  can give slightly higher current carrying capacity on long runs, but is insignificant on a short length as is being proposed.

    When terminating large single core cables, beware eddy currents in ferrous metals ! Aluminium is fine, but double check that this is actually used and NOT STEEL.

    A large bonding conductor is probably required between the aluminium gland plate and the main switch-gear enclosure. Reliance on the fixing bolts is unwise at this sort of current.

    I would use cleats that support all four cables,.

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