Power and Connector Standards

I have probably ranted about this before, and in some ways I know my rant will not produce change or make my life any easier, but once again I find myself baffled at the lack of standards…. or should I say abundance of standards…. Usually I would complain about USB connector types or Power supply adapter plugs. This time though, I am complaining about your standard run of the mill power plug… Yes the one that goes into the wall and provides AC power.

 See – that is the one that we all know and love (in north america anyway)…..

Now I understand the need (especially when it comes to Electricity) to ensure you cannot plug a 120 Volt device into a 250 Volt circuit, but the subtlety in which these cables were designed is horrendous.

Cisco send me a new 4507 RE catalyst switch… Big beast with two 1300 Watt Power supplies. Now I took electricity in high school and college and thought I knew a thing or two about it —-Apparently not!!!

P=IE – one of the few formulas that I remember…. P is Power (Watts), I is Inductance (Current/Amps) and E is Voltage.

In Canada the Voltage is 120.

The Power supply is 1300 Watts.


1300=I x 120

Therefore I = 1300/120

Therefore I = 10.83 Amps. Or at least I though so…..

So why do I need a 20 Amp Service… Any why did the cable they send me conform to the 250 Volt Standard. But it’s not only my math that is flawed..As I said the subtle difference between two standards is so close you can’t see it until you try and plug it in.

 Can you see the difference…. Easy when there side by side….One is 250 Volt and the other is 120 Volt.

Or how about this one…..

 OH – that’s right…. The first one is 30 Amps and it is slightly bigger that the other.

 and my personal favorite…. Only because it lost me another day…….

I am not blaming the electrical industry…..In this case I’m blaming Cisco for not clearly indicating what Power cord will be coming with the unit and not clearly indicating what type of power I need for a specific product. If it falls outside of the standard it should be CLEAR as to what the requirement is.

And please – I would be happy for someone to point out the error in my math……




REF: http://www.stayonline.com/reference-home.aspx


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