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Lozzyf

Hook up to wattage calculation?

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Can anyone explain SIMPLY how to calculate what you can run in wattage from your hook up without flicking the trip? . That is on a 16 hook up thanks .

 I’m thinking of getting a halogen plate but am wondering how I can use it if we have a teppanyaki grill (1500watts) also going and maybe heating/hot water . . . . . . 

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I've always gone by, watts = amps x volts as a guide.

John

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In UK divide watts by 230 e.g. 1500/230 = 6.5 amps as near as darn it!

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16a is about 4000 w . Even if you run your heating on 2 kw you should be fine .

 

Does it run on full heat ? I run a induction hob that is 2 kw but it works with ten heat settings at 200 w steps so I use only the first 5 heat settings so under 1000w.

 

 

Dave

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Keeping it simple, (and approximate):-

On a 16A hookup you get up to 3.5 Kw (3,500W).

If you have your grill on, and a 2Kw water heater, that's your lot!

Turn off the water/space heater and you have plenty for a halogen plate.

Because of the way thermostats work, you may, sometimes get away with more but don't bank on it!

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Well as a very very rough simple guide I use  

 

4 amps will run 1000 watts =  1 KW 

6 amps will run 1500watts = 1.5 KW

10 amps will run 2500watts = 2.5 KW

16 amps will run 4000 watts = 4 KW 

 

M

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I think most induction hobs regulate power simply by turning on at off, so a 2kW hob will use a continuous 2kW at full power.  At lower 'power' settings it will go from 2kW to zero and back again.  This is how my kitchen cooker works and my portable hob.

 

UK voltage is actually 240V.  My kettle will consume 2520W at 220V, but 3000W at 240V so if close to the limit look at the rating plate on each appliance and use the higher figure.

Edited by kelper
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Many caravans have the internal circuits split between two circuit breakers, one at 10A the other at 5A, so any limit will depend what else is in use at the time.

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As stated above Watts @ = Volts x Amps.  So 1kW = 4amps as near as makes no practical diffference.  So 1500W is 6amps.  I can work that out in my head. Which why I don’t both worrying about U.K. voltage being a nominal 230V. 

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Just now, fred said:

As stated above Watts @ = Volts x Amps.  So 1kW = 4amps as near as makes no practical diffference.  So 1500W is 6amps.  I can work that out in my head. Which why I don’t both worrying about U.K. voltage being a nominal 230V. 

 

UK voltage can be as high as 252 but is normally around 240 - the nominal 230 is the standardised fudge across the whole of Europe to cover the wide range of actual voltage.

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26 minutes ago, kelper said:

I think most induction hobs regulate power simply by turning on at off, so a 2kW hob will use a continuous 2kW at full power.  At lower 'power' settings it will go from 2kW to zero and back again.  This is how my kitchen cooker works and my portable hob.

 

UK voltage is actually 240V.  My kettle will consume 2520W at 220V, but 3000W at 240V so if close to the limit look at the rating plate on each appliance and use the higher figure.

 

I states in the instruction book how many watts at each setting uses at about 200 w per step .

 

 

Dave

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1 minute ago, Black Grouse said:

 

UK voltage can be as high as 252 but is normally around 240 - the nominal 230 is the standardised fudge across the whole of Europe to cover the wide range of actual voltage.

On the belief that at various locations the mains voltage extremes are between 220V and 250V giving extremes between, 3.5kw and 4kw I just assume worst and work to 3.5kw

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An additional tip.

Place a label giving the current each appliance draws at 250V on that appliance. That will serve to remind you not to exceed whatever the current limit is for the EHU you are using, simply by adding up the numbers on the tags. Remember that if the supply voltage is lower than 250, the current will reduce proportionally, therefore by calculating at 250V you will always be within the supply limit.

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the way that I work things out in the 'van is that if I have the heating on then I can have 2 other large appliances on.  However none of my appliances are as much as yours. Heating  4kw, and microwave 5kw,    are the highest, of course the charger and the fridge  are always on. I  look at the wattage of the items when I buy them, the kettle is a travel kettle and the toaster is a basic cheap toaster, not too many watts on the basics, but still I always check them. 

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The OP should also check the ratings of the MCBs in his caravan. There should be a 6A for the charger, water heater and fridge (and any mains lighting), and <usually> 16A for the power sockets (which includes the microwave and electric room  heating.) However I have seen caravans with 6A and 10A breakers to ensure that the total current drawn shouldn't (in theory at least) exceed the 16A rating of the blue connectors. Such MCBs would limit the socket power consumption to 2KW so a domestic 3KW kettle is a no-no. You will find that some sites also limit power from the pillar to 10A (supposedly) for safety but also to keep consumption down for the site owner.

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1 hour ago, Gordon said:

An additional tip.

Place a label giving the current each appliance draws at 220V on that appliance. That will serve to remind you not to exceed whatever the current limit is for the EHU you are using, simply by adding up the numbers on the tags. Remember that if the supply voltage is higher than 220, the current will reduce proportionally, therefore by calculating at 220V you will always be within the supply limit.

. . . .you see Gordon THAT is where my head goes to mush! . . . . Current. . . Volts . . . . Amps . . . . Wattage . . . ..???? 
If my teppanyaki is 1500watts  what label do I stick on it?🤷‍♀️

37 minutes ago, Woodentop said:

The OP should also check the ratings of the MCBs in his caravan. There should be a 6A for the charger, water heater and fridge (and any mains lighting), and <usually> 16A for the power sockets (which includes the microwave and electric room  heating.) However I have seen caravans with 6A and 10A breakers to ensure that the total current drawn shouldn't (in theory at least) exceed the 16A rating of the blue connectors. Such MCBs would limit the socket power consumption to 2KW so a domestic 3KW kettle is a no-no. You will find that some sites also limit power from the pillar to 10A (supposedly) for safety but also to keep consumption down for the site owner.

 . . . I’m a “she” btw but that aside I will be using my outside plug socket . . So I’m guessing 16A ? But won’t the pillar trip before any of my fuses ?

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4 minutes ago, Lozzyf said:

. . . .you see Gordon THAT is where my head goes to mush! . . . . Current. . . Volts . . . . Amps . . . . Wattage . . . ..???? 
If my teppanyaki is 1500watts  what label do I stick on it?🤷‍♀️

 

Volts x Amps = Watts

Watts / Amps = Volts

Watts / Volts = Amps

 

So 1500w / 220v = 6.8 A

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2 minutes ago, Grandpa Steve said:

 

Volts x Amps = Watts

Watts / Amps = Volts

Watts / Volts = Amps

 

So 1500w / 220v = 6.8 A

Have screen shot this

2 hours ago, montesa said:

Well as a very very rough simple guide I use  

 

4 amps will run 1000 watts =  1 KW 

6 amps will run 1500watts = 1.5 KW

10 amps will run 2500watts = 2.5 KW

16 amps will run 4000 watts = 4 KW 

 

M

And screenshot this as I won’t blinking remember! 👍🏼

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3 hours ago, Gordon said:

Remember that if the supply voltage is lower than 250, the current will reduce proportionally, therefore by calculating at 250V you will always be within the supply limit.

Not so, Gordon!

Because the resistance or impedance remains constant higher voltage means higher current and wattage. Give a heating appliance an over voltage and it will run hotter and draw more current. 

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3 hours ago, Lozzyf said:

. . . . I’m a “she” btw but that aside I will be using my outside plug socket . . So I’m guessing 16A ? But won’t the pillar trip before any of my fuses ?

Woodentop should go to spec savers :D

 

I just work on the basis that if anything with a high wattage/ amps is going to be used, then switch off the heater and the ehu pillar will not trip. Saves having to get the warden out to reset it. Plus our kettle is a 750 watt one which takes ages to boil but is not going to result in any trips of mcbs.

Edited by Paul1957
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Keep it simple-never mind fluctuations-work on worst case scenario-dividing by wattage of the item by 240 and round up if necessary-nice and simple and never fails us. We initially made a list on paper of all the amps drawn by all our items-but we generally now stick to -lower amp sites ie 10amps heating and 1 item, 16 amp site we sometimes treat ourselves and go for 2 and by big items i mean high current draw-kettle microwave etc-we don't worry so much re tv etc! But by the time we have the tv on we're generally on the gin n tonic or wine!

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UK mains voltage is not 240... it's 230.  The permissible range is -5%to +10% or 218 to 253V.

 

Whilst Watts=Amps x Volts is ok for resistive loads (heaters with no motor element) any inductive load (e.g. electric motors) the starting current draw will be much higher than a resistive load

Edited by Guzzilazz
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10 minutes ago, Guzzilazz said:

UK mains voltage is not 240... it's 230.  The permissible range is -5%to +10% or 218 to 253V.

 

Whilst Watts=Amps x Volts is ok for resistive loads (heaters with no motor element) any inductive load (e.g. electric motors) the starting current draw will be much higher than a resistive load

 

The NOMINAL voltage is 230v but the actual voltage in the UK is around 240v - the wide permissible range isto allow a European nominal of 230v to be declared without any country having to change it's system voltage.

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1 hour ago, Guzzilazz said:

UK mains voltage is not 240... it's 230.  The permissible range is -5%to +10% or 218 to 253V.

 

Whilst Watts=Amps x Volts is ok for resistive loads (heaters with no motor element) any inductive load (e.g. electric motors) the starting current draw will be much higher than a resistive load

 

1 hour ago, Black Grouse said:

 

The NOMINAL voltage is 230v but the actual voltage in the UK is around 240v - the wide permissible range isto allow a European nominal of 230v to be declared without any country having to change it's system voltage.

The OP asked for "simple"!

Keeping it simple, if approximate, 1Kw is  just a bit over  4A.

16A is near enough 3.5Kw.

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FWIW I witnessed a main voltage being measured last week.  It was 247.7V. This was measured with a fully calibrated traceable instrument btw.  230V is a nominal voltage not even a target voltage.    So you don’t really know the voltage. Then if something claims to be 1.5kW what is the tolerance on that?   The breaker is 16A does that trip after a current of 16.01amp after 1 second nope.   This question is often asked and always ends up with people giving unrealistically precise answers.   

 

1kW equals 4amps and if calculating the  consumption is getting close the limit is getting close maximum capacity then switch something off especially if it is raining or the trip is in a locked cabinet. 

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