Fixed 110v installation advice

Hi all,

Just in the process of planning a 110v install in a small workshop.

Using a 2kva (centre tapped 55-0-55) wall mount transformer, first question is regarding the primary protection for the transformer, the primary current is around 9a but seem to be getting conflicting views regarding the appropriate MCB to feed the primary. Seem to see figures between 125% and 250% to allow for inrush - I was thinking a 20a D rated MCB should do the job but would appreciated thoughts on this!

The transformer will feed 8 (not all will be used at once - only a one person workshop) 16a commando sockets (radial). The transformer has no built in overcurrent protection on the secondary so was thinking of a small db with a double pole mcb. Even though the commando sockets are rated 16a is it suitable to use a 20a C rated mcb as it is a radial (and transformer output is around 18a)?

Thanks in advance for your input - not used to this 110v!

Parents
  • I second sparkingchip's advice

    we use 5kVa transformers to run 2.2kW grinders, anything less and they start to trigger the thermal overload, which takes ages to reset.

    If they use a shop vac on it, it will definitely trip out in fairly short order. 

    Screwfix seem to be the cheapest way to get Carrol & Meynell transformers

    the transformers have a continuous rating that is half of the sticker rating don't forget

Reply
  • I second sparkingchip's advice

    we use 5kVa transformers to run 2.2kW grinders, anything less and they start to trigger the thermal overload, which takes ages to reset.

    If they use a shop vac on it, it will definitely trip out in fairly short order. 

    Screwfix seem to be the cheapest way to get Carrol & Meynell transformers

    the transformers have a continuous rating that is half of the sticker rating don't forget

Children
No Data