2 appliances into a 3 amp switch ?

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  #1  
Old 09-06-15, 04:14 AM
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2 appliances into a 3 amp switch ?

Apologies my knowledge of electricals is awful!

I have a 3 amp switch which is protecting a small (2ft) florescent lamp. This seems like overkill to me as we have a trip switch consumer unit, but let that pass. We have just bought an extractor fan which needs to be connected to a circuit. The closest point to connect it to is this 3 amp switch. I am not concerned about the fan being on the lights circuit. I was wondering if anyone could tell me, is having the extractor fan and the florescent light running through the same fuse likely to overload (will each be likely to be sending 2 amps through thus overloading the switch ?) or is this a reasonable if not ideal way to wire it up ?

Thanks
 
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Old 09-06-15, 04:32 AM
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Welcome to the forums! Most of us are not very knowledgeable of European electrical set ups since this is primarily a North American forum. Terminology is quite different. What are you calling a switch? We use switches when we enter rooms to turn on lights. I think you may be referring to a breaker in a panel. What is the wattage of the fluorescent fixture and that of the fan?
 
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Old 09-06-15, 05:28 AM
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Hello, many thanks for answering.

The switch is a wall switch with a fuse in the same small panel. It may be a "double pole switched fused spur outlet" but I'm only saying this because it looks like a picture of one ! I suspect it is there because it is in a fairly cheaply done extension and whoever did it did it in a rough and ready but safe way (i.e. they didn't redesign the wiring or put in a consumer unit (I have had one put in since) but they did put a properly fused spur in)

The total rated power consumption of the extractor fan is 108W and the florescent bulb is 18 watts.

Thanks again.
 
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Old 09-06-15, 06:45 AM
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We also need to know the voltage to determine amps, but I believe most EU voltage is in the 220-240 range. If that is the case your current draw is only about .6 amps (126/220=.57) I think you are in very little danger of overloading the fuse.

In the US fuses/circuit breakers are installed to protect the installed wiring not connected equipment. Equipment will normally only draw what it is designed to draw. A 100 watt light bulb will draw .83 amps on a 120 volt circuit regardless if it is on a 15 amp circuit or a 100 amp circuit. The installed wiring of the branch circuit only needs to be sized properly.
 
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Old 09-06-15, 06:53 AM
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Thanks. Yes it is a 230 volt supply. I must get a book as I feel ashamed to know so little!

I think most circuit breakers here (UK) are designed to protect the wiring although in this case the instructions were talking about protecting the appliance. I saw someone renovating a flat in France the other month and that was a whole different ball game ! I think there they do protect the appliances as well. The consumer unit had about 40 trip switches for a 2 bedroom room flat. In the UK it tends to be 1 for all lights, one for all sockets, 1 for the cooker etc. I think it may be to do with us having an earth in the wiring and the continentals not doing so but I'm falling out of my depth again ;-)
 
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Old 09-06-15, 07:58 AM
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No worries! Most electrical theory and info can be found on the internet. Things like Ohm's law is a good one to learn. Electrical installation vary greatly from country to country, and has evolved over the years in any one country, so sometimes it can be difficult to give exact info.
 
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Old 09-06-15, 10:14 AM
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In your search for info try England and ring circuits.
 
  #8  
Old 09-06-15, 06:20 PM
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Yes, even in the U.S. fuses and breakers in the panel are supposed to protect the appliances, lights, and fixtures also, within limits.

There is a maximum amperage of the circuit on which you are permitted to wire up the appliance as well as a minimum. If the maximum is greater than 20 amps then the appliance instructions or name plate should state what that maximum is.

Lights, appliances, electronics, etc. for use on general purpose 120 volt circuits in the U.S. must be designed for use on 20 amp circuits in order to pass U.S. safety standards even though the actual amps draw is much less. Also the plug (cord cap) implies the maximum amperage circuit for using the light or appliance. Sometimes there will be an internal fuse or breaker with a lesser rating if the equipment needs more protection. Such a fuse is often found in electronic equipment and Christmas tree lights.

Because of the maximum amperes for a circuit to serve a specific appliance, it is often that several small or medium amperage branch circuits need to be run, often serving one appliance each as opposed to one high amperage branch circuit serving several appliances.

... In the UK it tends to be 1 (breaker) for all lights, one for all sockets, 1 for the cooker etc. ...
How many amps were the breakers rated for? Are we just talking about older homes where originally there were very few appliances being used and perhaps a maximum of 30 amps for the entire house?
 

Last edited by AllanJ; 09-06-15 at 06:38 PM.
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