I've mounted a 16 socket power distribution strip on the wall behind the computer desk. It plugs into a single 13 amp socket and has a 13 amp fuse in the plug. Currently I'm only using 9 of the sockets but the screen and modem are powered off the computer. On the other side of the room I've got an 8-way distribution board serving a Mac, desk lamp and other equipment.
If this room reverts to a bedroom in the future then I can just remove the power strip and free-standing board, and maybe replace the two single sockets with doubles.
As for fire hazard the main problem with old fashioned adapters is that the socket isn't designed to take the weight of several adapters, plugs and flexes. You can easily get arcing which can start a fire, but also as most of the old adapters don't have internal fuses you can overload the socket too. The ring main is of course protected by it's own fuse which is fine as long as there isn't an undetected break somewhere.
Power distribution boards connected through fused plugs don't suffer the same problem as they have flexible leads and either sit on the floor or are securely mounted to walls, desks, cabinets, etc.
My mistake, I just checked and it's 95 watts. It's quite large and a pain to remove, but your post prompted that I should check. I seem to recall reading someone's obviously erroneous post on google that TV's were in this range (500-800 watts), and as my TV was large, used the maximum figure.
At a company I previously work for I managed to obtain a 2nd hand HP 19" rack for a load of our group's development kit. For a while this was served from one 13amp plug, connected into a "building facilities" supplied 4 gang thralling strip. which in turn was supplied from someware under the floor!
In the rack we had something like the following
2 x Sun e250 servers (with 2 hot swap 250w psus each).
2 x Compaq 1600 PIII servers
1 x HP procurve Switched hub
1 x Cisco 4000 router
1 x HP Surestore scsi disk array (12 hds and dual psu's very heavy!)
1 x Blackbox "KVM"
Later we obtained our own dev room and had 2 racks with another 4 odd sun ultra 10 / 40 workstations and a monitor connected to a single 2 gang socket. When there was a power cut the inrush tripped the MCB supplying that socket!
Because there were electricians working elseware on site It took about 2 days to arrange for a second socket!
In the racks them selves I had wired everything into HP PDU's these have a 16A IEC supply connector (plus one 16A IEC daisy chain connector) and abt 8 10A IEC sockets for equipment. There pretty substantial and have two mcb (live and neutral I'd guess). I think I had 4 of them for the
Actually, it may take 5-800W, in a .1 second surge at switchon, while the degaussing coil does its thing. Most of the time it'll be at the lower figure though.
Leaving aside the maximum earth-loop impedance - which, IIRC, depends on the type of installation - to have any validity extension leads which are daisy-chained in this way need to be PAT tested as a single appliance. From memory (but my memory isn't that good these days!) the earth continuity on a PAT test should be below 0.5 Ohm. Although, as a domestic installation, this set-up probably doesn't have to be PAT tested, I'm fairly sure that it would fail if it were.
French 2 pin plugs are very compact compared to our british ones. I dont know if its now possible to get ones with half insulated pins and cord grips: when I saw them years ago they were hopelessly unsafe.
Yes, the HP PDU's do have little current trips in both poles; I vaguely hope that they're mechanically interlinked somehow, but have never bothered to find out or test (e.g. by rigging up a bench test where only the N side of one of these PDUs is used, the L feeding from Somewhere Else). Here in the UK, we're enjoined by the Regs to have protective devices only in the phase conductors (L for single-phase, L1/L2/L3 for three-phase) or a mechanically interlinked setup such as in double-pole signle-phase RCDs. The HP PDUs are, I suspect, a US design, where the 220V comes from two opposite-phase windings each at
120V relative to earth, so fusing in both of the live conductors is appropriate.
Incidentally, there was a safety recall on a batch of these exact PDUs a couple of years ago; if you're still at the place with them, it's worth a look (we sent letters to direct-customers-of-first-instance and to distrubutors/resellers, but the longer the distribution chain (and the larger the purchasing organisation!), the greater the chance of the letter not reaching anyone who can actually Do Something About It). Ah yes, here it is:
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"HP to Replace Limited Number of Power Distribution Units to Resolve Potential Safety Issue
PALO ALTO, Calif., Feb. 9, 2001
...HP has informed customers that a safety hazard may result if the internal primary safety ground of the PDU is inadvertently interrupted.
..."
with a further pointer to a truly corporate-paranoia "think of the lawsuit" Letter To Customers at
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paranoid bit is where we say "only look for the serial number if you haven't installed the PDU yet. Otherwise, STEP AWAY FROM THE RACK. DO NOT TOUCH THE RACK. LET A QUALIFIED HP SERVICE ENGINEER RISK THEIR LIFE. ONCE AGAIN, STEP AWAY FROM THE RACK. ASSUME THE POSITION. DO NOT PASS GO. DO NOT COLLECT 200,000,000 DOLLARS IN EMOTIONAL DAMAGE AND BUSINESS INTERRUPTION DAMAGES. OBJECTS IN THE MIRROR MAY LEAD TO GREATER LIABILITY THAN MAY APPEAR. HOT COFFEE MAY CAUSE SCALDING. NUT BARS MAY CONTAIN NUTS. SAFETY GOGGLES NEEDED WHEN COLLECTING CONKERS!!!!" Oh, the relevant markings are "Made in Ireland", with serial numbers IR00007626 to IR00083460.
HTH - Stefek (still working for HP, though not for much longer if our Legal Department suggests I'm making light of a customer safety issue!)
I did wonder about that. They did look like two descrite trips. I was of the oppinion that it's better than nothing and there was a 13a fuse in the plug, and the strips were rated to 16a incommer at 240v. There were also RCD's on the distrution boards.
ekk that legal bit is a little scary. Thanks very much for the warning. I've just sent an e-mail to a friend who looks after the rack now. If there's no earth and the two trips are floating then prehapse that's the source of the problem? hmm....
Got any techi server type jobs in the reading area going?!
They're also a blasted nuisance where the mains sockets are in floor boxes with an access lid (as we have at work), since the lid won't go sit down again flush afterwards. So you're put in the situation of having to buy a 4-way trailing adapter to plug in the wallwarts externally, which detracts from the otherwise neat appearance.
When I was there they were using 2 pin round pin plugs, not the same as our old British 2 pin round pin ones. They fit into British square pin sockets, and typically had no cord grip, the pins typically screwed in to hold the conductors, with a piece of card covering the underside live bits, and sometimes copper whiskers would poke out from round the pins. They were anything but safe, so I wouldnt be surprised if they've changed to Schuko by now.
Must admit I hadn't thought of it. There's plenty of space under the suspended floor for deeper boxes, though the cost of retro-fitting them throughout the building would far outweigh the aestethics of having them, and we're a poverty-stricken university dept (ahem.)
Instead of buying 4-way strips, in future I might try Stefek's idea of a single trailing socket on a short extension cable for wall-warts only. That can be tucked out of sight, Velcro'd to the back of desks, etc. more easily.
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