# How much current does it take to injure me? [duplicate]

I'm building a 5 V and 4 A circuit that will be in contact with the body.

How can I know if this amperage, in case something goes wrong, will not be a problem for my health or my life?

## marked as duplicate by pipe, winny, Marcus Müller, JRE, SamGibsonNov 19 '18 at 13:10

• well, your body and the intended circuit form a current divider. Hence, the amount of current flowing through you will depend on the voltage of the supply. Not on how much current it's currently supplying. For example, a supply pushing 5A through a 100mΩ resistor will not be dangerous to you, at all – that only requires 0.5 V, and your skin resistance will be high enough to not allow for dangerous current to flow through you. Now, pushing 5A through a 1 kΩ load will require 5 kV, and that will pretty much kill you,because then your body resistance isn't high enough to avoid significant current – Marcus Müller Nov 19 '18 at 9:35
• But. this question has been asked in various forms here before: Search for "do volt or ampere kill me" and similar. – Marcus Müller Nov 19 '18 at 9:35
• which part of your body? if it is your external skin and you stop when it gets uncomfortable there will be no harm. – Jasen Nov 19 '18 at 9:38
• Something else you need to consider: If the 5V and 4A are coming from a line powered power supply (you plug it into an outlet in your home) then you may be exposed to higher voltages that can kill you. – JRE Nov 19 '18 at 12:09
• If you are connecting it to your body, do not power it from an outlet. From your question, you do not have the knowledge and experience needed to design and build a line powered device that can be safely attached to a human being – JRE Nov 19 '18 at 15:15