A dimmer rack itself won't consume too much power. A bit of control electronics, perhaps some cooling fans. What you really need to know about it is what loads (lanterns) are connected to it. Very difficult to say what your rig uses as it depends what lanterns are in use, how many simultaneously and so on. If you have 6 channels of dimming, each rated at 10A, then then the load per channel will basically not exceed 10 (Amps) x 240 (Volts) = 2400W per channel, ie 6x2400=14400W = 14.4kW You might happen to know that all your lamps are 1000W and therefore you won't be exceeding 2000W per channel, ie 6x2000 = 12kW Your dimmer rack might be fed from a 63A 3 pole MCB, in which case it basically draws up to 3 (phases) x 63 (amps) x 240 (volts) = 45kW. It's not quite this simple, and the feed may not be able to handle every channel at full load (eg not uncommon to have a 32A three phase supply feeding 12x10A dimmer channels, ie 40A per phase)