Page 4 of 6

Re: 10 amp 15 amp ??

PostPosted: Mon Jan 30, 2012 4:03 pm
by 8-ball
panda sorry if i offended you with my remarks of offering help to others and what is supposedly unsafe ie its better than grinding off the earth pin to a 15 amp plug but if a moderator would actually remove my posts about making a makeshift adapter it would be appreciated and would make it a happier and safer place

ps Panda i reckon you would be a valuable asset to have around here

8-ball out :handgestures-thumbupleft:

Re: 10 amp 15 amp ??

PostPosted: Mon Jan 30, 2012 4:42 pm
by MacStill
So how many watts can I safely use through a 15amp outlet ?

I'm going to run 4400watts on my new boiler, possibly more if it's safe to do so.

Re: 10 amp 15 amp ??

PostPosted: Mon Jan 30, 2012 4:49 pm
by R-sole
AxV = W

so 4400 wats dived by 240 v = 18.3 amps...


sorry...buh booowwwhhh

Re: 10 amp 15 amp ??

PostPosted: Mon Jan 30, 2012 4:59 pm
by stubbydrainer
If my calculations are correct, I can run 6000w safely from my welder socket

A x V = W

35 a x 240 v = 8400 w is the max for the outlet .......Correct or not ? :think:

Re: 10 amp 15 amp ??

PostPosted: Mon Jan 30, 2012 5:15 pm
by 8-ball
OhmsLaw.jpg
P = V x I (amps)
both 5Star and stubby are right but i work voltage as 230 as its the lowest allowed by energex ( according to energex's tech services guy and my old tafe teachers )



oi Mcstill out of curiosity whats the max power/ max amps that plasma cutter/welder what ever this argument got started over ??

Re: 10 amp 15 amp ??

PostPosted: Mon Jan 30, 2012 7:54 pm
by Panda
My understanding is that with an element, resistance is actually your fixed value and not the given wattage. Assuming the advertised wattage is based on the rated voltage, you can calculate the resistance and then calculate the current draw (this could be proved or disproved using a multimeter)

Eg;
Your element is 4400watt, I am going to take the liberty of saying it is a 250volt element for this example.
We have 2 main rules.
Amps x volts = watts (as stated above)
Amps x ohms = volts

How to Find resistance.
4400watts / 250volts (elements rated voltage)= 17.6amps
250volts / 17.6amps = 14.2045455ohms ( elements resistance)

Dividing you mains voltage by this value will give you your current draw and multiplying that given ampage by supply voltage will give you the elements effective power.

(rounded figures)
At 220v supply it will draw 15.5amp and give you 3407watts of energy
230volt 16.2amp 3724watt
240volt 16.9amp 4055watt
250volt 17.6amp 4400watt

From this you could choose what plug size is needed (I assume it should be based on 250 or 253(230 + 10%) but do not know)
And depending on the health of voltage in you area you can see what power you will actually recieve from an element (you can see at 220 - 230volt you have lost a bit of juice). Depending on your situation, Both of these figures should help you choose an element better.

Re: 10 amp 15 amp ??

PostPosted: Mon Jan 30, 2012 8:04 pm
by Panda
8-ball wrote:panda sorry if i offended you :

I'm sorry too

Image

Re: 10 amp 15 amp ??

PostPosted: Mon Jan 30, 2012 8:06 pm
by stubbydrainer
Panda
the power outlet I'm going to use is a 240 v - 35 amp outlet, it has my 250 amp welder on it and is a dedicated( til now) circuit I had put in the shed. the welder goes good at full amperage, ie: flat out, I have had it welding 25 mm plate and boring it uppa.
so I think the "quality of power is good , even though we are at the end of the line ( I know this because of the bill of power poles , transformers etc,)
So I feel safe with 2 x 3000 w elements

Edit : I dont really understand electicity but I reckon that bit of maths you just put up is interesting, and could maybe use those maths to go to 7200 w :laughing-rolling: :laughing-rolling: :laughing-rolling:

Re: 10 amp 15 amp ??

PostPosted: Mon Jan 30, 2012 8:20 pm
by Panda
stubbydrainer wrote:Panda
the power outlet I'm going to use is a 240 v - 35 amp outlet, it has my 250 amp welder on it and is a dedicated( til now) circuit I had put in the shed. the welder goes good at full amperage, ie: flat out, I have had it welding 25 mm plate and boring it uppa.
so I think the "quality of power is good , even though we are at the end of the line ( I know this because of the bill of power poles , transformers etc,)
So I feel safe with 2 x 3000 w elements

6000 watt at 250volt is 24amp,At 230volt is 26amp well below the 35 amp capacity. there would be no need to try and nut out exact figures

Once you know the resistance and do the math, Lower voltages in a resistive load will actually result in lower ampage draw so will not pose a danger, but will lower the heating capacity of the element. Finding the resistance of the element is really the key to knowing what amps it will draw and what power it will deliver more so then the said wattage.

Re: 10 amp 15 amp ??

PostPosted: Mon Jan 30, 2012 8:25 pm
by MacStill
Anyone wanna know how to operate an excavator?

Fortunately my experiences with electricity has been minimal :laughing-rolling:

Good to see this thread back on track. :text-thankyoublue:

Re: 10 amp 15 amp ??

PostPosted: Mon Jan 30, 2012 8:27 pm
by Cane Toad
Hey Stubs,that means you can sqeeeeeeze another 2400w element in there somewhere,correct? :handgestures-thumbupleft:

Re: 10 amp 15 amp ??

PostPosted: Mon Jan 30, 2012 8:28 pm
by Cane Toad
Hmmm makes me wonder what I can run on the 15kva genset when it turns up :laughing-rolling: :laughing-rolling:

Re: 10 amp 15 amp ??

PostPosted: Mon Jan 30, 2012 8:35 pm
by stubbydrainer
that puts me in theoretical debarkle, ( but it's not a real problem)

I like to nut things out as best I can before building stuff, and here's the problem
All the so called Calculators re: boiling water with amps , watts volts etc , need the wattage of the element/s inputs before it calculates,
and now you just inform me that I need to measure the resistance of the element to find out what output it will have, so In actual fact I have already got the elements and its to late to worry about the calculators to find out watt elements to buy coz I've already got the elements, I had to measure them
what comes first the chicken or the egg :laughing-rolling: :laughing-rolling:
As I have already stated it's not a problem for me , but That would totally fuck me up if I was a pedantic some bitch :-D

Re: 10 amp 15 amp ??

PostPosted: Mon Jan 30, 2012 8:37 pm
by stubbydrainer
I'd probably run it on diesel BD :laughing-rolling: :laughing-rolling: :laughing-rolling: :laughing-rolling:
Crickey BD, ya just gunna singe the wash that way :laughing-rolling: :laughing-rolling:

Re: 10 amp 15 amp ??

PostPosted: Mon Jan 30, 2012 8:39 pm
by MacStill
stubbydrainer wrote:that puts me in theoretical debarkle, ( but it's not a real problem)

I like to nut things out as best I can before building stuff, and here's the problem
All the so called Calculators re: boiling water with amps , watts volts etc , need the wattage of the element/s inputs before it calculates,
and now you just inform me that I need to measure the resistance of the element to find out what output it will have, so In actual fact I have already got the elements and its to late to worry about the calculators to find out watt elements to buy coz I've already got the elements, I had to measure them
what comes first the chicken or the egg :laughing-rolling: :laughing-rolling:
As I have already stated it's not a problem for me , but That would totally fuck me up if I was a pedantic some bitch :-D


Fark me! I'll just stick to digging cables up :text-lol:

Re: 10 amp 15 amp ??

PostPosted: Mon Jan 30, 2012 8:44 pm
by Cane Toad
Yeah something lime those big space heaters you see in the colder climes hey,or what about those big gernies you see at big mechanical workshops?when da water comes out of them it's boiling and almost instantly :handgestures-thumbupleft: :handgestures-thumbupleft: Bugger all waitin round then

Re: 10 amp 15 amp ??

PostPosted: Mon Jan 30, 2012 8:45 pm
by stubbydrainer
I was operating a digger at a site once were they called me "the reverend" Coz I never missed a service, I got 32 except for one I would have got them all.
Plumber said " Nah mate , get into it , there's nuthin there, it been located , and even if there is , it's obsolete , so just fucking rip into it :laughing-rolling: :laughing-rolling: :laughing-rolling:

Re: 10 amp 15 amp ??

PostPosted: Mon Jan 30, 2012 8:54 pm
by Cane Toad
If Mac finds one out where he is it'll be a fukn doozie :laughing-rolling: :laughing-rolling: :laughing-rolling:

Re: 10 amp 15 amp ??

PostPosted: Mon Jan 30, 2012 8:57 pm
by Cane Toad
Yeah I spose I'll need one of those voltage controller thingies,but I don't think it's gunna fit in no bloody ammo box though :laughing-rolling: :laughing-rolling: :laughing-rolling:

Re: 10 amp 15 amp ??

PostPosted: Mon Jan 30, 2012 9:11 pm
by MacStill
It would be good if we didnt drag this too much off topic, I'd love to see a graph put together of what volts/watts/amps & general home use type of stuff....... would be a great asset to the forum and it's members if we had some simple safe guidelines to follow.

Would be a great addition to "tips from the workshop" and of course no liability goes anywhere but to the individual doing DIY lectrics.