I have read many times about how it is beneficial to wire 4-20ma loops using twisted pair, however what if the wiring is 3 wire (i.e. +,- and signal)? Does this mean that you simply use screened three core? Does this mean you use two twisted pair and if so what one is the single?

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4-20ma Cabling - 3Wire

Les Spiteri over 5 years ago

I have read many times about how it is beneficial to wire 4-20ma loops using twisted pair, however what if the wiring is 3 wire (i.e. +,- and signal)?

Does this mean that you simply use screened three core?

Does this mean you use two twisted pair and if so what one is the single?

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0 Alasdair Anderson over 5 years ago

Sorry, but I am a bit confused by this. If you have a wire for the signal (i.e. carrying a current of between 4mA and 20mA) then where is the current going? Surely there needs to be a return current, so which is the return wire?
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0 Alasdair Anderson over 5 years ago

Sorry, but I am a bit confused by this. If you have a wire for the signal (i.e. carrying a current of between 4mA and 20mA) then where is the current going? Surely there needs to be a return current, so which is the return wire?
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4-20ma Cabling - 3Wire

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