easy amperage question

[zachtheterrible]

Our vaccum says that it runs @ 11 amps. I know that half an amp is enough to kill somebody, and that some circuit breakers say 15 amps on them. Our power is 120v ac. Does it REALLY run @ 11 amps, or is that just an exaggeration?

 

[andrew2022]

Our vaccum says that it runs @ 11 amps. I know that half an amp is enough to kill somebody, and that some circuit breakers say 15 amps on them. Our power is 120v ac. Does it REALLY run @ 11 amps, or is that just an exaggeration?

it prob does run at 11 amps altho unless u state the power i cant say for sure. if it is 11 amps at 120v, then 120x11=1320w. also, anything above 50 volts can kill you, anything less shud not kill you (due to body resistance, altho direct to the heart a small voltage can be lethal). theCB is 15amps cuz u dont want a 5amp runnin a 11amp hoover. also you will have otha stuff plugged in... it all adds up and must be under the CB rating

 

[zachtheterrible]

If it all adds up, and you have 2 11 amp vaccums running on a 15 amp circuit breaker, wouldn't it pop the breaker?

 

[olly_k]

can I ask you what the link between death by electricution, your 15A power breaker and the vacuum cleaner is?
Can I assume you are confusing the power breaker with a Residual Current Device?
If I remember clearly anything above 50mA (1/20th Amp) accross the heart is enough to put the heart into VF - and basically kill you if expert help is not around at that very moment.
Anyway, most RCD's will trip if a current of more than 30mA (although larger RCD's are available) flows from either live or neutral to earth. i.e. if there is an imbalance between hot and return.
A circuit breaker however being a re-settable fuse, will open if the current flowing exceeds that by which it is set. i.e. if you plug too many vaccum cleaners into the same 15A circuit!

 

[zachtheterrible]

u did read my first message, right? Well, I'm just wondering if the vaccum cleaner actually draws 15 AMPS, or if it means something else about the cleaner. r u sure that 50 ma will kill someone? I thought it was 500 ma, or a half an amp. 1000 ma = 1 amp, right? (i think i might be gettin' this confused). Also, i know that i'm not confusing a circuit breaker w/ an rcd. What is an rcd by the way?

 

[Exo]

It depends on the power of your vacuum cleaner (in Watts, usually printed somewhere on the tag)

Current used (I, in amps) = Power (P, in watts) / Voltage (U, in volts)...

So, if you have a 1000Watt vacuum and your voltage is 120volts then
1000/120 = 8,33 Amps...

Calculate for your cleaner, and yes, if you run 2 of those on a single 15A circuit breaker it will switch off (maybe not directly if it just 'on the edge')

 

[Nigel Goodwin]

u did read my first message, right? Well, I'm just wondering if the vaccum cleaner actually draws 15 AMPS, or if it means something else about the cleaner. r u sure that 50 ma will kill someone? I thought it was 500 ma, or a half an amp. 1000 ma = 1 amp, right? (i think i might be gettin' this confused). Also, i know that i'm not confusing a circuit breaker w/ an rcd. What is an rcd by the way?

With your low mains voltage I would expect your cleaner to take 11A as it says, as already suggested, simply work it out from the wattage. Cleaners seem to be getting more powerful as time goes by, 1800W is common in the UK (where we have higher mains voltage and more power available).

UK mains (as is all the EU) is 230V, we use 13A three pin plugs, with internal fuses. These plug in to 'ring mains' circuits, you would commonly have a seperate ring for upstairs and downstairs, each ring would have it's own fuse or circuit breaker at the distribution board - lights have their own circuits, as do high power circuits like cookers and showers, all with their own fuses or circuit breakers.

The advantage of 230V is that you can have higher power appliances, I understand that in the states you have to have special 220V sockets for high power appliances?. We can use a single appliance of about 3000W, it's a common rating for kettles and heaters.

An RCD is a safety device with turns your power off if there's a small leak of current to ground - they come with a number of different names - GFI may be one you are more familiar with?.

 

[olly_k]

I thought it was 500 ma, or a half an amp. 1000 ma = 1 amp, right?

you are right as far as 500mA is 1/2 or 0.5 Amp, but 500mA accross the heart would kill anyone stone dead, and I should imagine with irreversable damage. I am 100% sure it is 50mA (0.05A) which would make sense to selecting 30mA for the RCD trip value. Although it should really be said that 30mA caould equally kill. Really the best thing to remember is that ANY current flowing in any part of your body can be fatal!
As far as me confusing the issue by mentioning an RCD was because I was a little confused by your link between the three things you mentioned in the original post, and couldn't see any other link...
I thought you were implying that a circuit breaker couldn't trip if someone touched the 'hot' wire,if it was rated at 15A, which is correct. So I assumed you were missing a component that works differently to a circuit breaker which would trip when the above occurs..
Do you see where I am coming from?
Or am I complicating what was really a simple question??? :roll:

 

[pebe]

.... I am 100% sure it is 50mA (0.05A) which would make sense to selecting 30mA for the RCD trip value. Although it should really be said that 30mA caould equally kill.....

Yes, I believe an RCD is designed to trip at 30mA in a maximum time of 30mS.

 

[zachtheterrible]

I sort of missed the fundamentals because I am trying to teach myself everything through books, and they didn't really touch on this subject very well. I don't know what I would do w/o this forum. Anyway, I've got another question. I'm going to use the human body for an example again only because it is something that we can all relate to, not because I am going to try and kill someone w/ electrocution. Ten volts will produce ten amps of current if there is 1 ohm of resistance. Of course ten volts couldn't force 10 amps through the human body (I=v/r). So let's say that we have a transformer stepping up the voltage to a point where there is so little amperage, it wouldn't kill someone. If you connected the 10 volts to either side of the secondary of the transformer, would that huge voltage push 10 amps through someone? (I swear i'm not going to kill anyone)

 

[Nigel Goodwin]

So let's say that we have a transformer stepping up the voltage to a point where there is so little amperage, it wouldn't kill someone. If you connected the 10 volts to either side of the secondary of the transformer, would that huge voltage push 10 amps through someone? (I swear i'm not going to kill anyone)

No, it wouldn't - regardless of how you connected it. From how I read what you said, you would be paralleling the high voltage and the low voltage - in which case the low voltage would short out the high voltage. If you connected them in series, the high voltage would limit the current to what it was able to supply.