Installing socket under floor boards

[davejuk]

ban-all-sheds: You have been poison from the start. For you to tell me to lighten up is laughable. Sarcastic or not, most of your posts in this thread are unhelpful and they detract from the odd constructive comment you drop in. Whether I meant to refer to your third or fourth post, the point remains. I missed your third post because you made it just minutes after your second one. Presumably you hit the submit button prematurely after getting over excited about having another dig at me. Your fourth post is clearly aimed at me. Stop being such a smart ass.

With regard to the power supplies, the PoE standard will require that the switch is capable of delivering so much power over each port which is why the PSU might seem overkill. Still, it says 30W max on the spec: http://www.cctvdiscover.com/megapix...ssories-c48_51/port-10100m-poe-switch-p4.html

Picture of PC PSU:

Untitled

• davejuk
• 5 Aug 2012
• 1

Picture PoE switch PSU:

Untitled

• davejuk
• 5 Aug 2012
• 1

I will try and measure actual power consumption tomorrow.

 

[JohnW2]

Picture of PC PSU:

Untitled

• davejuk
• 5 Aug 2012
• 1

What on earth does "5.0-2.75A max" mean?

Picture Picture PoE switch PSU:

Untitled

• davejuk
• 5 Aug 2012
• 1

If they really did draw as much as they say when delivering their maximum stated output, they would probably get pretty hot ('rekindling'some of the previously-expressed concerns!), as well as costing you significant money to run continuously.

I will try and measure actual power consumption tomorrow.

That will certainly be interesting. I would have expected/hoped for a small proportion of the total power consumption you are suggesting.

Kind Regards, John.

 

[bernardgreen]

Measuring the power input will be difficult as with all low cost switch mode PSUs the input current only occurs during the peak of each mains cycle and readings on an RMS ( root mean square ) meter will not be valid for calculating power from volts times amps.

I suspect the 1.5 amp input current is the peak current taken as a short pulse 100 times a second.

The printed " 12 - 14.5 volt 5.0 - 2.75 amp " may be the extremes that the unit can "safely" produce but if the 60 watts maximum at 12 volts drops to only 40 watts at 14.5 volts then I would consider the output stage is operating on limits of some of its components. As a result I be very suspicious about the units reliablity.

 

[bernardgreen]

Why not have a disposable, (maybe a dummy or defunct ) recorder almost concealed that the intruders, if clever enough, will find and remove thus assuming they have the CCTV recordings. While a better concealed recorder, concealed but not in a position where it might present fire risk, also has the recordings.

 

[ban-all-sheds]

ban-all-sheds: You have been poison from the start.

Don't be ridiculous.

For you to tell me to lighten up is laughable. Sarcastic or not, most of your posts in this thread are unhelpful and they detract from the odd constructive comment you drop in.

From your POV most of the posts full stop are unhelpful, because that's your opinion on any which so much as suggest that you might do something differently.

Your fourth post is clearly aimed at me. Stop being such a smart ass.

It is not. Stop being such a jerk.

 

[LUG]

Stick the cctv recorder in the loft. Burglars don't go in lofts...........normally.

Andy

Thats not what our friendly neighbourhood watch policeman tells us.

 

[SimonH2]

BAS - davejuk makes a valid point. While you usually have something useful to say, and your knowledge of regs seems to be encyclopaedic, you frequently post in a manner which indicates (at best) a reluctance to accept that different opinions held by others can be valid. I've seen comments from a few others along these lines.
It's not uncommon that your useful comments are completely missed because of this.


davejuk and JonW2
As to the PSU ratings, you usually have to ignore the values on the rating plates ! It's something endemic in the IT world, and if people managing facilities worked on rating plates, they'd need to over-spec supplies by a very large margin.
That PC PSU is a good case in point. For 60W at 100V which is the worst case for input current, the actual current would be only 0.6A - plus whatever extra for the PSU losses. At 240V it's only 0.25A. Same for the other one as well. So we can only speculate as to where the numbers actually come from - my guess is that they are "just made up".

PoE provides (in it's current incarnation) a max of 15.4W/port, which means in excess of 60W if all ports were fully loaded. The actual power drawn will depend on the equipment attached - the phones we use at work only draw about 3-5W each, but I know some cameras can be marginal*. If the power drawn exceeds the limit for a single port then it will be turned off. If the total drawn would exceed the total capacity of the switch then not everything will be turned on.

* I recall problems we had with a customer in SA. The camera would crash every night because when the IR illumination turned on, it drew too much power for the PoE supply. When I heard this, my first reaction was along the lines of "golly, wasn't that a bit of an oversight to design a camera with PoE that can't run from PoE" (or words to that effect).

 

[RF Lighting]

I've seen simialr with a PTZ dome camera wired on a single cat5. 1 pair was for video via baluns, 1 pair for PTZ contol signalling, and the remaining 2 pairs for power. The camera switched on and displayed a picture until it started moving to reset the pan / tilt position, at which point it crashed, and started again in a never ending cycle!

 

[davejuk]

Thank you for your comments. Here is the data I promised.

Temperatures from CPUID/HWMonitor (deg. C) collected over 2 days.

Description, Min, Max

SYSTIN, 28, 65

CPUTIN, 36, 156*

AUXTIN, 36, 155*

Core 0, 30, 77

Core 1, 27, 76

HDD, 26, 48

* WTF

Power consumption:

34W with PC, switch and 2 camera connected and recording. During start up 40W was the highest value.

21W with PC idle, nothing else connected

11W just the switch, 2 camera connected

8W just the switch, 1 camera connected

4W just the switch, no cameras

 

[SimonH2]

Right, so the cameras are only taking 3-4W each, and the PC around 25W. That's not going to overheat under the floor.
In fact, I;d suggest that under the floor is possibly one of the better places - generally reasonably cool even in hot weather. Unlike the loft which typically does an impression of an bake oven on days like we've had here today.