Providing earth for small transformer

[williaminsurrey]

Hi - I bought a small transformer when I moved to the UK so that I could still run some of my small 110/115V electrical appliances. The transformer I have is described here (Model 170B):

http://www.hammondmfg.com/pdf/5c0073.pdf

The diagram seems clear enough as to how to wire it up to go from 230V to 115V, but it seems there is no provision for an earth.

Obviously the transformer should have an earth? Can I simply fix the cpc in the flex to the outer shell of the transformer?

Thanks in advance.

 

[Taylortwocities]

Was this purchased in the US/Canada?

Be very careful with this auto transformer. With 230v across the winding you will have NO personal protection. There appears to be no provision for the case to be properly earthed and (in the UK) it should have.

If it were me i would buy something designed with our voltages and safety requirements in mind like this: http://www.tlc-direct.co.uk/Products/SC5497.html

If you are determined to use it at least run it from an RCD on the 230V side and earth the transformer case. Carry the earth thru to the 110v device u are plugging in if it has a 3-pin plug.

 

[bernardgreen]

There appears to be an over length bolt through the laminations. This MAY be a suitable place to connect an earth to the metal work of the unit.


As mentioned this will only provide a 110 volt "tap" from the 240 volt supply and must not be considered as an isolating device.

The incoming earth from 240 side must be taken through to the earth in the 110 volt socket as well as being connected to the frame / exposed metal work of the transformer

Do not use a UK 13 amp socket for the 110 volt as some time in the future the 110v device will be accidently plugged into a 230 socket. Use US style plugs and sockets

 

[Stoday]

The transformer is intended to be mounted in a box. It has flying leads, which will be single insulated and quite unsuitable for connecting to the 230V mains.

A metal case would also include 110V sockets and either a 230V input plug or a flexible cable with a 13A plug on the end. The earth would then be connected to the metal case.