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Posted By Topic: adding a heat pump to a house with tiny mains

Oct 20 2018 18:41

at a house today and noticed the mains in were 2.5mm, it has an electric oven gas hob and hot water and is a large old villa. A \'Professional\' company has come along and put a large heatpump in....
What obligations do they have to check that the household power can take this kind of load before installing?

Oct 21 2018 11:13

One of the important steps any installer must follow before connection of additional loading takes place, is that all cabling (including the mains and associated switchgear) has the ability to carry the increase in loading that the new work will provide.

Failure to do so, could mean that the electrical installation has become electrically unsafe, which is covered by ESR 2010, due to the ability to be not being able to carry the increased current demand.

Remember the three options of AS/NZS 3000 to control the maximum demand, and it the limitation option is used, the electrical installation is \"NOT fit for purpose\" in some circumstances.

In this case the fitting of a MCB as the main switch to limit the loading to the mains or switchgear current capacity, would result in an electrical installation being unfit for purpose.


Oct 21 2018 22:35

Is this 2.5mm feed really to a house or is it s submains from another board?

Oct 22 2018 07:09

it joins directly into the nuetral screen coming in from the street, not uncommon in central wellington, although rare on a full size villa

Oct 22 2018 10:51

Ive seen this in welly its rather odd. Had to replace it as it melted