Electrical Contact Voltage Drop Diagnostic Tool — Find Connection Losses
Estimate voltage drop and heating at a contact, terminal or connection from measured current and resistance, then compare the result with a user-selected diagnostic threshold.
Contact measurements
Why a small contact resistance can matter
Connection resistance can be much smaller than conductor resistance, yet high current can make even a low resistance produce measurable voltage drop and local heating.
Voltage drop
Contact voltage drop is simply current multiplied by contact resistance. Reporting the drop as a percentage of system voltage makes the result easier to compare with a chosen review level.
Heating
Power dissipated at the contact follows I²R. This means a current increase can have a disproportionately large effect on contact heating.
Diagnostic use
Unexpectedly high voltage drop or localized temperature rise can indicate a connection that deserves inspection, but the calculator cannot identify the physical cause.
Limitations
Real connections may be nonlinear, temperature-dependent or affected by pressure and oxidation. Use suitable measurement and inspection methods for actual troubleshooting.
Frequently asked questions
Can resistance be zero?
Yes mathematically, producing zero drop and heating.
Does this calculate conductor voltage drop?
No. It isolates one contact or connection.
Can the result exceed the review level?
Yes. The tool flags that condition without claiming that a universal limit has been exceeded.