Dimmers on low voltage

[vertigodj]

Been at college today and had a discussion on SELV circuits regarding lighting, cable selection etc. Question came up about using dimmers on selv lighting with the tutor saying in his notes basically not to use them because of problems that they may cause to cable / lights. On further questioning on this subject it was suggested that with reducing the voltage on the circuit ie dimming the lights on the primary side of the transformer the current increases on the secondary side of transformer making the cable depending on how many lights you have insufficent to take the current.So as i understand this now, if i had installed selv lighting with normal control gear ie. a single/double pole switch and calculated correctly apropriate cable to serve this circuit,then decided to install a dimmer instead of switch - cable then would not be suitable ?

 

[Taylortwocities]

Tosh. Good quality dimmers with dimmable transformer is no problem on the primary side of the transformer. No need to upgrade/change wiring at all.

How can the current go up if the light is being dimmed? Think about it.

There's a guide re dimmers at http://www.tlc-direct.co.uk/Technical/DataSheets/Systems/DimmerGuide.htm

 

[securespark]

Ask your tutor how he would feel if you used both an SELV transformer suited to dimming & an SELV dimmer rated for that tranny?

Edit: Pah!!

 

[vertigodj]

Thats how i understand it but just double checking. Will clarify with tutor on this subject again, thx for replying.