Is 4-20mA Current Range Safe for Human Body Contact?

Hi I need to know how much current range human body can handle what about the current ranges between 4-20mA is it possible??

Hi Derby-If you're asking if it's safe to touch a 4-20mA loop circuit- yes, it is. You wan't feel a shock even if you touch the connections while they are live.HOWEVER- if you are asking if the body can handle a current of 4 to 20 mA- that's a different question entirely. In the case of a 4 to 20mA loop, the current would not be flowing through the body, mainly because the voltage involved is low and the skin resistance is fairly high. If you were to actually flow 4 to 20 mA through the body it would involve higher voltage.  Potentially dangerous voltages. Possibly even lethal under certain circumstances. NEVER intentionally flow current through the body unless you're certain you know what you're doing and are fully aware of the risks.  The rare occasions to intentionally pass current through the body would be in the case of defibrillators  or electrocautery machines. If in doubt, DON'T DO IT!-Rick    

HI Derby,
I agree with Rick and would add that what might be safe for one person may not be for another. Even the path through the body will change the susceptibility of electrocution, so do not get involved unless you have to.Conrad

As an aside to the above, RCDs (Residual Current Devices) or ELCBs (Earth Leakage Circuit Breakers) are now mandatory on power circuits in many countries.  They work on detecting an imbalance in the currents between the Live (Active) and neutral lines of a power circuit.  Any time there is more than (typically) 30mA of difference between the two, they will trip and disconnect the circuit.  That is what happens when a human touches a live part of the circuit - the current flows to earth instead of back to the neutral.  30mA is reckoned to be the highest non-lethal current a human can tolerate.  And you can easily get this level of current if you touch a live wire, depending on how wet / sweaty you are, and how good your connection with earth is.  I have found this out to my cost on several occasions, but thankfully I am still here :-)As Rick points out above, the voltage on a 4-20mA current loop measuring circuit is much lower than the 110 / 230V mains power voltage, typically 24V or less.  If you stuck that on your tongue while standing on a good earth with wet feet you'd get a good jolt, but not much otherwise.

Hi David,Very good points and in my house (UK) I have each lighting and power circuit covered by individual ELCB's, to improve on circuit discrimination.
Like you, I have had my share of unwanted connections to the mains supply.I would suggest that one should follow medical advice and get your heart checked if you connect across household voltages or above. I once was working on a high voltage high current DC test set when the cage safety interlocks  failed, while I was setting up the next test piece. The ionised air was the only warning that I got that the control room had energised the site. It was the last time I ever used lever switches on any test site. Conrad

I just need to know the feeling of electric shock to human (who is standing on ground) at mentioned 4-20mA current  if we are touching the live wire which is connected to 24v DC  Yes I agree at very high power transmission huge risk will be there which can cause damage to our body also.

Hi Bart-You probably won't feel it at all, but it's still best to avoid contact whenever possible.  Since you mention standing on the ground- I always make sure I have shoes with good insulating qualities.  I would never depend on them to protect me, but they add an extra layer of safety.-Rick 

Bartif we are touching the live wire which is connected to 24v DC
If I interpret this correctly- if you are touching the 24VDC line of a 4-20mA current loop,  the 4-20mA has nothing to do with the current that flows through the body.  The body conducts from the 24V to ground. See the other comments above, especially David’s.

Bart - Aubrey is spot on - it does not matter whether the 24V is coming from the line of a sensor, or a truck battery, or a lab power supply - what matters is the resistance of the body.  Try the following experiments:(1) get a digital multimeter (DMM) and set it to a high ohms range.  With dry hands, grab one probe tight in each hand and note the resistance.  Now wet your hands (maybe even use salty water) and try it again.  The reading should be much reduced.  Also try putting both probes on your tongue (ONLY do this with a battery powered DMM).   Result - the wetter the contacts, the lower the resistance.(2) increase the contact area by using clips onto some bits of metal - PCB, aluminum foil, etc., again the better the contact area, the lower the resistance.(3) get one of those mini 9V batteries, and hold it onto your skin at various points - again try dry and wet skin.  You might feel a slight tingle if you're lucky.  Now touch the battery connections onto your tongue.  With a good new battery you'll definitely feel it, a lot more than on your skin.As I said above, 24V onto your tongue standing on a good earth with wet feet, might give you a bit of a jolt, but usually touching 24V you would not even feel.  50-60V is usually when you would normally start feeling something.