Thats the view I took from everyones responses. I have ordered a copy of the latest IEE wiring regs (I need an upto date copy anyway) I have already (whilst this thread has been on going) spoken to my boss about improving signage and additional training for all engineering types (IT and...
The risk is minimal, anyone who takes the lid of kit whilst 2x different phases is live is asking for trouble. The scenario could (not would) be if equipment power shares using 2x independent PSU's running from different phases. Even in this condition using switch mode psu's the effect is...
Yes, this hang up is alive and well....
As long as proper precautions are taken and there is proper labels and idents used I have no problem in having different phases near to each other. The view that you have shared has only very recently been removed and cables in racks within easy reach...
Yes, I can provide details for you, look at this website ( I cannot post a web address), so.....look for tslproducts dot com , then find power management followed by automatic change overs. "MDU14-CO" I hope this helps, if you need more information or even photos of actual installations and I...
Also if these two UPS feeds also provide power to a dual mains MDU, (please see previous posts regarding dual mains MDU's feeding equipment running on a single supply) In this case it is imperative to make sure the two UPS phases are the same.
Hello, This is to provide a safe working enviroment. We dont need the possibility of 400v across two PSU's running on different phases, why take the risk? It is the preferred practice within Broadcast systems to have dual supplies within a piece of kit to be fed from two UPS systems (main and...
All UPS systems (used in broadcast) are linked together (control wise) so that the Red, Yellow and Blue phases between UPS's remain in sync. You are correct that the outgoing phase maybe be different (not much) from the incoming because of the conversion from ac to dc and back to ac. But when...
The electrical system in all studios and play out centres are as follows;
The incoming three phase feeds 2x (or more) UPS systems via fuse and switch boards. Each UPS can (or should) power the entire station in the event of a power failure. Most UPS systems will only have enough power to run for...
Hi, Most PSU's are indeed switch modes and since they are "floating" until the DC has been converted from the hi frequency supply. That said, it is common practice to use the same phase for A and B UPS feeds. In the case of an dual mains input MDU (mains distribution unit) most of these units...
Normally in Broadcast kit, wiring diagrams are kept away from the racks, but often copies are pinned to walls for easy reference. BUT in our case, where we have 3 phase feeds into one rack (A + B) I will add more warning labels and colour code them as well.
Hello Rob, you're right in what you say. But since the equipment has 2x power supplies fed via IEC connectors. Both PSU's must be fed from different UPS's but on the same phase. In our case it could be very easy to get this wrong and have 2 different phases in the same piece of equipment, hence...
Many thanks for the replies, better than I dared hoped for.
The 3 phase PDU's installed (power distribution units) have 3 banks of IEC connectors and are labelled Circuit 1, 2 and 3. Not very clear which phase is which though. Each piece of equipment often has (not always) 2x power supplies...
I work in Broadcast television as a broadcast systems designer. I have seen in recent months a trend that is worrying (not sure if it is legal) that in a 19" rack there could be several phases wired to power distribution outlets (normally via IEC connectors) This means it is imperative that...
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