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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 back up ) BUT on the same phase.
You've got 400V between phases going on in loads of other OB kit, that in reality people are more likely to open up for whatever reason, such as dimmer packs, distro, etc.
 
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?

What exactly is the risk? Just stating that there is 400V isn't describing the risk, just making a statement.
What scenario do you see occurring where someone will be exposed to this 400V?
 
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.
Can you provide a photo of one of these "dual mains MDU" units. I hope this isn't the posh title for a widowmaker. I'm particularly interested in the supply ends of the dual feed arrangements when one feed only is energised and the other disconnected.
 
Is this a documented or recommend practice,

Or

A we have always done it that way practice?

P.s not trying to be argumentative but I am struggling to see the reasoning behind it.

In the entertainment industry as a whole, and especially theatres, there is an obsession with 'phase seperation' or keeping the phases at least 2 metres apart.
This is a hangup from many many years ago when it is required by the regulations and people just wont let go of the idea.

From talking to some people in the industry you would think that 400V magically jumps out of the sockets and grabs anyone walking past if there's 2 phases within a mile of each other.
 
Can you provide a photo of one of these "dual mains MDU" units. I hope this isn't the posh title for a widowmaker. I'm particularly interested in the supply ends of the dual feed arrangements when one feed only is energised and the other disconnected.
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 will be very happy to provide something for you.
 
In the entertainment industry as a whole, and especially theatres, there is an obsession with 'phase seperation' or keeping the phases at least 2 metres apart.
This is a hangup from many many years ago when it is required by the regulations and people just wont let go of the idea.

From talking to some people in the industry you would think that 400V magically jumps out of the sockets and grabs anyone walking past if there's 2 phases within a mile of each other.
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, its all ok as long as people follow good practices when installing stuff and do not cross phases.
 
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 will be very happy to provide something for you.
I've not read the spec in detail, but that looks like a proper piece of kit, designed to the relevant EN standard and incorporating a two pole 'break then make' changeover switch... therefore I'm unsure why the two supplies need to be on the same phase.
 
What exactly is the risk? Just stating that there is 400V isn't describing the risk, just making a statement.
What scenario do you see occurring where someone will be exposed to this 400V?
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 unlikely to cause a problem. But why take the risk, minimal as it maybe. In Broadcast and related systems (editing, post production houses etc) often other non engineering types have access to power connectivity (when they shouldn't) and this is where problems could arise. Maybe it is considered to be overkill and you could be right, but ( I use this word a lot) we take safety very seriously and make sure there is no likelihood of having mixed phases no matter that the problems of doing so is minimal, i say again, why take the risk when we dont need too.
 
Ok, so going back to your original post, the answer is: There is nothing in the regs to say that this supply is incorrect.
If you wish to go beyond the regs then that it up to you.
How about training people not to mess with things they shouldn't mess with??
 
Ok, so going back to your original post, the answer is: There is nothing in the regs to say that this supply is incorrect.
If you wish to go beyond the regs then that it up to you.
How about training people not to mess with things they shouldn't mess with??
Don't cover stuff like this in the Boil in the bag courses Spoon, so it will be difficult to do what you ask, nice thought though.
 
Ok, so going back to your original post, the answer is: There is nothing in the regs to say that this supply is incorrect.
If you wish to go beyond the regs then that it up to you.
How about training people not to mess with things they shouldn't mess with??
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 Broadcast) as well as operators who should ask before twiddling with things they know little about. I am most grateful to the quality and variation of the responses I have had on this site. It has been most helpful.
 
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 unlikely to cause a problem. But why take the risk, minimal as it maybe. In Broadcast and related systems (editing, post production houses etc) often other non engineering types have access to power connectivity (when they shouldn't) and this is where problems could arise. Maybe it is considered to be overkill and you could be right, but ( I use this word a lot) we take safety very seriously and make sure there is no likelihood of having mixed phases no matter that the problems of doing so is minimal, i say again, why take the risk when we dont need too.

Again you've said 'why take the risk' without describing what the risk is.

I agree that safety should be taken seriously, but overreacting to something and putting excessive signs and labels on equipment makes it more likely for people to ignore those signs or not see the ones that really are important.
 

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