16A plug

[Bruce May]

long story short, if we use a plug which is 16A , and ofcoures it means the effective current, so how big can the real input current be?
And with that plug(16A), how it gonna influence the output current? duty cycle, I rekon PFC will be considered when come across such question.
Any answer will do..

 

[piman]

Hello Bruce,

the input current, under short circuit conditions could be many more times the 16 amp rating, but for practical purpose consider it as 16 amps. There is no input or output current as such, it is just current and the duty cycle depends on the size and type of circuit breaker (Which would be 16 amp assuming a single socket) Broadly speaking as the overload increases the time before the breaker trips decreases.

What exactly are you trying to do?

Alec

 

[madkayaker]

What are you trying to do? 16amp bs4343 must be protected by 16amp circuit protective device (there is allowance for a 20amp radial feeding multiple plug if the designer can confirm that is safe)

 

[rikrobson]

why not use a 32A socket and appropriate protection.

 

[Bruce May]

what am trying to do is, to figure out how big can the output current be when with the limited input power( 16A 240V), with and without PFC function.

 

[rtbcomp]

You won't get more output current than you put in, so if you've limited the input current to 16A the most you'll get out is 16A.

Assuming by PFC you mean Power Factor Correction, this is a measure of phase difference between voltage & current (I think) and as the voltage doesn't come into the current ratings for a plug & socket PFC is irrelevant.

 

[Robotstar5]

You won't get more output current than you put in, so if you've limited the input current to 16A the most you'll get out is 16A.

Assuming by PFC you mean Power Factor Correction, this is a measure of phase difference between voltage & current (I think) and as the voltage doesn't come into the current ratings for a plug & socket PFC is irrelevant.

Prospective Fault Current?

 

[rtbcomp]

Now you know why I insist on abbreviations being explained the first time they're used in a thread.

 

[Woody.v8]

I thought it was Popping Fuse Constantly

 

[madkayaker]

I thought it was Popping Fuse Constantly

Like it

 

[dannyp]

16 amps at 230v or 240v you'll get 3.7 / 3.8 KW

arc voltage is apparently anything between 20 and 50 volts

so worst case is 74 amps
best case is 190 amps

with 100% efficent inverter

as it's a constant current prosses the arc voltage is going to have a massive effect on power consumption


with the thermal arc inverter running 6013 rods i can usally get it to run on 110 - 120 amps on site without kicking the trip, anythign higher and the trip will go

 

[Bruce May]

a bit wrong

You won't get more output current than you put in, so if you've limited the input current to 16A the most you'll get out is 16A.

Assuming by PFC you mean Power Factor Correction, this is a measure of phase difference between voltage & current (I think) and as the voltage doesn't come into the current ratings for a plug & socket PFC is irrelevant.

input=16A 240V. then output must be 16A ? the output Voltage must be very lower than 240v and so the current will be much higher than 16A also...SO...

 

[Bruce May]

more likely...

16 amps at 230v or 240v you'll get 3.7 / 3.8 KW

arc voltage is apparently anything between 20 and 50 volts

so worst case is 74 amps
best case is 190 amps

with 100% efficent inverter

as it's a constant current prosses the arc voltage is going to have a massive effect on power consumption


with the thermal arc inverter running 6013 rods i can usally get it to run on 110 - 120 amps on site without kicking the trip, anythign higher and the trip will go

Thanks mate

 

[rich r]

As above - on a 16A socket you should have a 16A type C MCB. That's what's important.

On striking the arc when running 4mm rods at 150A you might see 20A being drawn from the supply for a split second, which is well within the MCB's specs. Once the arc has struck and you're actually welding, the current draw will settle down to under 16A.

If you're using 2.5mm rods you'll only rarely go over 13A (and that's only on initial strike), with 3.2mm it'll maybe spike just over 16A, but not by much.

 

[madkayaker]

As above - on a 16A socket you should have a 16A type C MCB. That's what's important.

On striking the arc when running 4mm rods at 150A you might see 20A being drawn from the supply for a split second, which is well within the MCB's specs. Once the arc has struck and you're actually welding, the current draw will settle down to under 16A.

If you're using 2.5mm rods you'll only rarely go over 13A (and that's only on initial strike), with 3.2mm it'll maybe spike just over 16A, but not by much.

Its not as simple as you must use a 16a type C MCB. It is down to the designer and installer to select suitable protection device. It is very common on caravan sites to see 10B MCB to reduce the maximum demand for the site.

 

[skotl]

Its not as simple as you must use a 16a type C MCB. It is down to the designer and installer to select suitable protection device. It is very common on caravan sites to see 10B MCB to reduce the maximum demand for the site.

Apologies for resurrecting a month old thread. I'm with Madkayaker on this - the design of the circuit and, in particular, the cable used is very important when considering maximum current draw.

The circuits are (should be) protected by a Miniature Circuit Breaker (MCB) which, as an aside, should not be confused with RCDs. A Residual Current Device (RCD) is designed to detect unbalanced current between the neutral and energized (aka "live") conductors. In other (simplistic) words, RCDs are to protect you from electric shock and MCBs are to protect the circuit and connected devices from over-current.

It may surprise you to hear that MCBs are designed to trip at much higher currents than the numbers stated on the devices. A "B-rated" MCB (which is the standard MCB fitted for most circuits) will trip at between 3...5 X total load current. So an MCB stamped as B16 will trip when the load exceeds ~48A.
Why the discrepancy? Because the MCB is there to detect grossly abnormal loads, not normal ones. There is also a factor called "diversity" which allows for the fact that not all devices will draw maximum current at all times and/or the same time as other devices.

Back to the original question; a welder will typically start with a massive surge of power, due to inductive load (as will devices with large electric motors, such as a lathe). It is quite common for these devices to have a startup current greater than 5x their nominal current consumption, and so a B-rated MCB can trip on startup.
At that point, you should consider a C-rated MCB for circuits that supply welders; C-rated MCBs have a trip rating of 5-10 x rated current.


And... so... we're back to the original question. Can you run (say) a welder that draws 16A or 20A on a 13A socket?
The MCB on the circuit needs to be considered, but the more important component is the rating (cross-sectional area or CSA) of the supplied cable and the length of that cable. 1.5mm CSA twin and earth will only sustain 16...20A for a relatively short run. A long run of 1.5mm cable really needs to be de-rated down to 10...13A

2.5mm cable can take more current, but it will depend on diversity calculations, cable lengths, whether it is a ring or a spur, etc.

Overall, the MCB tripping is a potential nuisance but the danger of overhearing the wiring and or switch gear is very real.
There is no right or wrong answer (beyond "don't go over 13A on a 13A socket") without having a qualified electrician evaluate the circuit and do the calculations.

Apologies for the lecture! Hope some of it helps

 

[Robotstar5]

It's a good job you didn't get into maximum disconnection times or you would have been sent to an electricians forum

 

[skotl]

It's a good job you didn't get into maximum disconnection times or you would have been sent to an electricians forum

I know where the thin red line is

 

[dan.taylor.1]

I thought it was Popping Fuse Constantly

Ah you've obviously tried to use a 9" grinder on one of our farm building sockets before...!

 

[dannyp]

got some chineese fuse you would love.

they say there 13 amp. it would appear they used some really big amps when testing them.

200A buzzbox going flat out 4mm and them 5mm rods failed to pop one