Testing a fuse.
26 February 2008, 03:10 PM
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Testing a fuse.
Have two fuses, in the old fashioned type consumer unit for the storage heaters, not sure if one of them is blown or not.
What settings should I use and what readings will appear on the multi meter for either possibility please.
They are 15AMP I believe
What settings should I use and what readings will appear on the multi meter for either possibility please.
They are 15AMP I believe
26 February 2008, 03:13 PM
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Needle or digital multimeter?
Set to ohms. Put the two pins together, needle should shoot over to the other end, not sure what digital reading will be. If it does the same with the fuse it means it's OK. If the fuse is blown the needle won't move.
Edit - I await correction, the more I think about it the more I think something's wrong...
Set to ohms. Put the two pins together, needle should shoot over to the other end, not sure what digital reading will be. If it does the same with the fuse it means it's OK. If the fuse is blown the needle won't move.
Edit - I await correction, the more I think about it the more I think something's wrong...
26 February 2008, 03:14 PM
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Set it to measure resistance. The screen will normall display "1" assuming its a digital meter. Touch a prong tp each end and it should read 0. If not, the fuse is blown.
Obviously do this with the fuse removed.
Obviously do this with the fuse removed.
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29 February 2008, 11:46 PM
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Depending on type, it might be possible for you to replace those cylinder fuses using a rocker type trip which replaces the fuse and carrier having two prongs which push-fit into the consumer unit. That way if one of your heaters is shorting out the supply and therefore blowing fuses it will then only trip the switch and you will be able just to reset it and try to isolate the cause.
As to your original problem as previously said the continuity buzzer (the symbol is a black triangle with a line through it) is the best way to test the fuse; if it beeps then that's a short and the fuse is ok. If fuses are failing you could use the meter set to resistance ( the symbol is a Greek Omega, set range to Auto) first to check between Earth and Neutral, and then Earth and Live on the heater side of the fuse carrier (turn the consumer unit off first, safety first and all that). Finally measure between Neutral and Live, if the fuse is 15Amp then the current draw if working is probably around 10ish Amps (single heater only?) so the resistance should read something around 20 Ohms across the heater element (Neutral to Live).
Before doing anything like this I would always use the meter set to AC volts (the wavy symbol) , put black probe to earth and use red probe to touch everthing you are going to play with to make sure there really is no live power.
If not confident then don't do it, just go for the fuse/trip replacement as the trips will give a visual indication of a problem (take the carrier to BandQ or an electrical factors to get the right alternative.
Kevin
As to your original problem as previously said the continuity buzzer (the symbol is a black triangle with a line through it) is the best way to test the fuse; if it beeps then that's a short and the fuse is ok. If fuses are failing you could use the meter set to resistance ( the symbol is a Greek Omega, set range to Auto) first to check between Earth and Neutral, and then Earth and Live on the heater side of the fuse carrier (turn the consumer unit off first, safety first and all that). Finally measure between Neutral and Live, if the fuse is 15Amp then the current draw if working is probably around 10ish Amps (single heater only?) so the resistance should read something around 20 Ohms across the heater element (Neutral to Live).
Before doing anything like this I would always use the meter set to AC volts (the wavy symbol) , put black probe to earth and use red probe to touch everthing you are going to play with to make sure there really is no live power.
If not confident then don't do it, just go for the fuse/trip replacement as the trips will give a visual indication of a problem (take the carrier to BandQ or an electrical factors to get the right alternative.
Kevin
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