Control Transformer Help

[450x]

Hello

I am building a control cabinet that is destined for Austria. In this cabinet are various devices that will accept input power from 85vac to 260vac 50/60Hz. I am going to install a 400:230 single phase transformer to power these devices. The size will be around 1 to 1.5 kva. I also want to provide a household plug to power trouble shooting equipment.

My question is with respect to grounding the secondary of the 400:230vac transformer. Should I ground the center tap or the bottom tap.

If I ground the center tap I will need 2-pole circuit breakers for all of my circuits?

If I ground the bottom tap of the transformer I only need 1 pole circuit breakers. If I do this, will it suitable for the household plug? The household plugs are of Type C(I think) They have 2 round prongs for power plus a ground prong. If I ground the bottom tap of the transformer it will meen two of the prongs for the plug will be grounded. Is this correct?

Thanks

 

[7anoter4]

First of all if you would ground the center tap it will be 115 V with respect to ground. The safety touch voltage according to DIN VDE 0100 is less than 50 V[ac] 120 V [dc].In order to protect person against direct contact you have to provide a sensitive residual-current-operated circuit breaker with a rated fault current less than 30 mA. As primary voltage is 400 V one has to ground at least one point of the secondary winding. The hosehold receptacle socket have to be provided with 3 contacts-one live, one neutral and one ground [or earth].
All the metallic parts of all appliances has to be bonded to ground.The neutral and the grounding wire has to be continuous without any breaker ,switch or fuse.
There is a possibility to avoid appliance bonding to ground if this device is double-insulated .Also, instead of residual-current-operated circuit breaker, one may use a rapid disconnecting means of maximum 0.2 sec trip time. But I don't
propose to use it instead.
Regards