Power Distribution Board Question

[Al Skierkiewicz]

Where to start?
Lets do the volts vs amps question. GFI breakers are designed to trip off at less than 4-6 ma since above that level is the current that seems to interrupt the heart function with regularity. However, at much less than 120 volts (the RMS value) the skin and body resistance will limit that current. That is why you can touch the terminals on the 12 volt battery and not be harmed. 48 volts on the phone line can give you a really uncomfortable tingle. This is all assuming you do not already have some electrical issue with heart function or have a pace maker. As you increase voltage the induced current will change. If the current is limited in some fashion, the high voltage still can cause other effects like local skin burns and muscle damage.
As Jim has pointed out above, high voltage requires precautions with insulation and exposed conductor spacing. The transmitter I work on has a 35,000 volt, 2 amp power supply. The wiring has a multi-layered insulation that requires regular replacement to prevent it breaking down. All the parts that are at this elevated voltage also have an anti-coronal design so that the voltage has a uniform field around the parts. This prevents discharge and the accompanying arc burns and localized welding of parts. There are no sharp edges on anything in the high voltage cabinet. Yes, at 2 amps, the wiring really needs to be only #22 wire. However it is larger than that simply to support the insulation and other factors. The overall diameter is about 1/4".
On to the power rating, yes the 35kV@2 amps gives you 70kW which is the amount of work that can be performed and this transmitter is generally capable of making 30kW at full power due to inefficiencies and head room. Here is where things get a lot more complicated. The RF at that level behaves much differently than DC of the same peak voltage. Even at low currents, severe muscle damage can occur with severe burning. The currents tend to flow at the surface of conductors and depending on frequency can penetrate the body to varying depths.
As to the PD, the conductor spacing, board composition and other factors would easily handle at least 50 volts and likely 100 volts DC. (The electronics as I mentioned above are designed for 12 volts and will be destroyed at 24 volts and above.) However, whether the PD would pass electrical laws (i.e. NEC) for those levels is unknown. I think that the WAGO is speced up to 300 volts. However, the current PD in my opinion, is far superior to the power distro used in earlier years. At least you do not need multiple tools to terminate wires and it is much easier to mount and use.