​1. How It Feels: The “9V Battery Test” on Steroids
​Your lips and tongue have very thin skin, moisture, and high nerve density, bringing local resistance down to under 1\text{ k}\Omega.
​If a broken cable or miswired mic accidentally shorts one of the +48\text{V} signal lines (Pin 2 or Pin 3) directly to the metal grille/chassis, touching your lips or tongue to the mic while your feet or hands are grounded creates a direct circuit:

The Result:
​Immediate Reaction: A sharp, burning sting or electrical bite on the tongue/lip, instantly triggering a muscle flinch to pull away.
​Metallic Taste: Severe electrochemical reaction (saliva electrolysis), leaving a strong metallic/copper taste.
​Physical Harm: It can cause a minor local burn point or blister if contact is sustained, but it cannot stop your heart or cause ventricular fibrillation (which requires much higher current paths across the chest cavity).

The Real Threat: Mains Ground Loops (AC Voltage)
​If a singer gets a dangerous or severe shock from a microphone, 48\text{V} phantom power is almost never the culprit.
​The real danger on stage is 120V / 230V AC Mains voltage:
​The Scenario: A singer is holding a grounded metal microphone plugged into the main PA system, while touching a guitar or guitar amp connected to a different wall outlet.
​The Fault: If the guitar amp or PA system has a lifted ground, faulty wiring, or reverse polarity, a massive AC potential difference (often 60\text{V} to 120\text{V} AC) builds up between the guitar strings and the mic grille.

The Danger: Touching your lips to the mic while holding the guitar completes an unlimited AC circuit straight across your chest and heart. This is what causes severe injury or electrocution on stage.
​How to Prevent It
​Never Lift AC Mains Safety Grounds: Avoid using “ground lifter” 3-to-2 prong adapters on guitar amps or PA equipment to solve ground hum.
​Use Wireless or Foam Windscreens: A foam windscreen provides a physical barrier so your lips never make direct metal contact with the grille.
​Check Cabling: Regularly test XLR cables with a cable tester to ensure Pin 1 (Shield) is continuous and Pin 2/3 aren’t shorted to the outer shell.

Run GFCI / RCD Protection: Always plug stage power into Ground Fault Circuit Interrupter outlets when performing outdoors or in damp venues.

To humans? No, absolutely not. To certain audio gear? Occasionally, if you aren’t careful.
Here is the breakdown of why 48\text{V} phantom power is completely safe for you, along with the few edge cases where it can damage equipment.
1. Safety for Humans (Zero Danger)
For electrical shock to be dangerous, you need enough voltage to break through human skin resistance and drive lethal current (milliamps) across the heart.
* Current Limiting Resistors: Per IEC 61938 standards, 48\text{V} phantom power (P48) is supplied to Pins 2 and 3 through twin 6.81\text{ k}\Omega current-limiting ballast resistors.
* Max Short-Circuit Current: Even if you grab Pin 2 or 3 directly with bare hands while grounded, the short-circuit current is hard-limited:
With human dry skin resistance typically ranging from 10\text{ k}\Omega to 100\text{ k}\Omega, the actual current passing through your body is under 2\text{ mA} — usually completely imperceptible or at most a minor tingle.
2. Equipment Risks (When Can It Cause Harm?)
While safe for people, phantom power can damage or destroy gear under specific conditions:
Vintage or Unbalanced Ribbon Mics
Modern ribbon microphones (or active ribbons requiring phantom power) handle P48 fine because the transformer isolates the ribbon element. However, vintage or passive ribbon microphones without output transformers can stretch or melt the thin aluminum ribbon if:
* The cable is miswired (ground shorted to a signal line).
* A patch bay or connector momentarily bridges Pin 2 or 3 to Pin 1 (ground) while plugging in.
TRS Patch Bays & 1/4″ Jacks (Hot-Plugging Short Circuits)
When inserting a 1/4″ TRS plug into a jack, the tip sweeps across the ring and sleeve contacts.
* If 48\text{V} is present on the jack, this momentarily shorts 48\text{V} directly to ground or across differential inputs before fully seating.
* Rule: Turn off phantom power before patching via TRS bays or standard 1/4″ jacks.
Unbalanced Gear / Consumer Audio
Connecting an unbalanced source (like a smartphone, synth, or consumer audio interface out) to an XLR input with P48 switched ON feeds 48\text{V} DC straight into the output stage of that device. Unless protected by blocking capacitors rated for >50\text{V}, this can burn out output transistors or op-amps.
Quick Reference Summary
| Connected Gear | Safe with 48V ON? | Notes |
|—|—|—|
| Condenser Mics | Yes | Required for operation. |
| Modern Dynamic Mics (SM58, etc.) | Yes | Pin 2 and 3 sit at equal DC potential (48\text{V} relative to Pin 1), so 0\text{V} potential exists across the voice coil. |
| Active Ribbon Mics | Yes | Built to use P48. |
| Passive / Vintage Ribbon Mics | Risky | Safe only if perfectly balanced; hot-plugging or bad cables can kill the ribbon. Turn off to be safe. |
| Synths, Guitars, Unbalanced Line | No | Use a Direct Box (DI box) to isolate P48 from line-level gear. |

I would love to hear how the ground of the mic (the negative DC supply) could cause this, and also how the ground of a phantom mic is different than the ground of a dynamic mic are different.

What does the 48V phantom power have to do with it? By the very nature of a phanto0m supply, the current is limited by the resistors in the mic preamp, and the + does not appear on the casing. If it did, then the 48V would be shorted to ground.

Dynamic mic automatically reject the DC voltage of a phantom supply, which is equal to both pins 2 and 3 of the XLR when phantom voltage is applied

That is NOT the issue, but often blamed by people who have no idea how phantom power works.

Lol phantom power is barely enough to power a small LED. This is an ungrounded guitar amp most likely.

Andrew Uher 48v can power 9 leds!

Ivan Beaver what if that cable is cut and no longer grounded, what if that pin is GONE. Explain Mr. I only work with grade A equipment paid for by the company I work for and have no idea how a current could mistakenly pass thru a metal object.. SYBAU

Rich YR If the ground wire is broken (or pin missing) a Dynamic mic will operate just fine, because the signal flows between pins 2 and 3.

A phantom powered mic will NOT work, because it has no negative of the power supply which is needed for operation.

But with either mic, if the wire is broken anywhere, then the case is not connected to anything, and therefore would not provide a path for anything, and could not cause what is being demonstrated in the original post.

“If the ground wire is broken (or pin missing) a Dynamic mic will operate just fine”
True
“A phantom powered mic will NOT work, because it has no negative of the power supply which is needed for operation.”
True
“But with either mic, if the wire is broken anywhere, then the case is not connected to anything, and therefore would not provide a path for anything, and could not cause what is being demonstrated in the original post.”
With a phantom powered mic with ground connection cut, there will be 48V phantom power through mic electronics on the mic metal body.
With dynamic mic, typically the signal wires inside mic are floating not connected to mic body, so no 48V phantom will not get to mic body. But it is possible that some mics can be built with built in center tapped transformer with center tap connected to ground pin – this would let the 48V phantom power to mic case.

Phantom voltage is supplied to the microphone via 6.81kΩ resistors on pins 2 and 3 (the return is pin 1, the cable shield). Pin 1 is typically connected to microphone metal body. If the pin 1 looses ground connection through the cable with classic dynamic microphone nothing happens (potentially mic picks more humming noise). If the microphone is phantom powered or has a built in audio transformer with output center point grounded to pin 1, the 48V phantom power cab get to microphone body.

https://www.facebook.com/share/v/1Cih5hq7vn/