YSTV's Mains Circuits

Basics

There are a total of 5 ring mains feeding 13A sockets in the station.

The control room has the 3 switched circuits (cct. 1, 2, and 3) and a permanent power circuit. The studio has permanent power sockets on the same circuit as the control room, and it's own switched circuit (cct. 4).

If something is used for editing and production, then it goes in circuit 3 (in the control room). Stuff for live shows goes on circuit 4 (in the studio), or circuits 1 and 2 in the control room. The only things that should be on permanent power are things that really need to be left on 24hrs a day, and the PCs that don't like being switched off suddenly.

Ratings

Each switched circuit is a ring main fed from a 40A MCB / 30mA RCD. The studio switch is on the wall by the control room door. The control room switches are on the wall by the phone.

The permanent ring is based on the original mains sockets when the room was a lecture room, and I'm not sure what the rating is.

The other three switched control room circuits are more recent than the studio conversion, and replace a single ring main from a switch unit on the wall of the Ents cupboard. This expired when Ents bashing of the wall managed to break the ring, converting it to a radial circuit, which then overheated and caught fire.

The current structure of 3 control room rings was then put in, because trying to put 18 Cub monitors onto a single circuit breaker would have tripped it straight back out on inrush current.

The studio is similar, with a single switched (by the door) ring main and the original 24hr sockets. The slight complication is that there aren't switched sockets in all the places there need to be, so the monitors on top of the cupboard, transfer rack, and other stuff over that side of the studio sit on permanent power and have to be turned off by hand.

The lighting dimmers are fed independently by two 32A radial circuits from the distribution board. Importantly, they are on the Yellow phase, where as the rest of the station is on Blue. Beware 400V between the two!

The techie room is just on the original 24hr sockets, so doesn't get an RCD. This means anything being tested in there, or any power tools, need to use a plug-in RCD.