Solar Engineering

NEC 690.7(c) PV String Voltage Correction for Lowest Expected Ambient Temperature calculator

NEC 690.7(c) PV String Voltage Correction for Lowest Expected Ambient Temperature engineering calculator.

Runnable This tool can run, but independent engineering verification has not been established.

Quick Answer

Calculate NEC 690.7(c) PV String Voltage Correction for Lowest Expected Ambient Temperature

Calculator

Maximum DC String Voltage (V)
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Result Interpretation

NEC 690.7(c) PV String Voltage Correction for Lowest Expected Ambient Temperature calculator computes Maximum DC String Voltage in V using the defined engineering formula and the input values provided. Maximum DC String Voltage is expressed in V. No universal acceptance threshold is defined by this calculator.

Worked Example

Verified calculation

Given:

  • Open-Circuit Voltage at STC = 40
  • Temperature Coefficient of Voc = -0.12
  • Record Low Ambient Temperature = -25
  • STC Temperature = 25
  • Number of Modules in Series = 12

Expected Result:

  • Maximum DC String Voltage = 3360

Engineering Interpretation:

Under the given input conditions, the calculated result is: Maximum DC String Voltage = 3360 V.

The actual numerical result is computed by the Runtime engine using the persisted tool definition. The values shown here come from deterministically validated test cases.

Formula / Method

maximum dc string voltage = open-circuit voltage at stc * (1 + (temperature coefficient of voc * (record low ambient temperature - stc temperature))) * number of modules in series

Formula family: formula_solar_pv_array_dc_string_voltage_calculation_per_nec_6907c

Variables

SymbolLabelRoleDescription
voc_stc Open-Circuit Voltage at STC INPUT Open-Circuit Voltage at STC
temp_coeff_voc Temperature Coefficient of Voc INPUT Temperature Coefficient of Voc
low_temp Record Low Ambient Temperature INPUT Record Low Ambient Temperature
t_stc STC Temperature INPUT STC Temperature
num_modules_in_series Number of Modules in Series INPUT Number of Modules in Series
dc_string_voltage Maximum DC String Voltage OUTPUT Maximum DC String Voltage

Calculation Steps

  1. Enter the open-circuit voltage at stc in V.
  2. Enter the temperature coefficient of voc in V/°C.
  3. Enter the record low ambient temperature in °C.
  4. Enter the stc temperature in °C.
  5. Enter the number of modules in series in 1.
  6. Step 1: Compute maximum dc string voltage.
  7. Read the maximum dc string voltage (V) from the results.

Engineering Summary

Calculate NEC 690.7(c) PV String Voltage Correction for Lowest Expected Ambient Temperature

Frequently Asked Questions

What does this calculator calculate?

The NEC 690.7(c) PV String Voltage Correction for Lowest Expected Ambient Temperature calculator estimates Maximum DC String Voltage based on the input parameters you provide

Why is open-circuit voltage at stc important in this calculation?

open-circuit voltage at stc is directly proportional to maximum dc string voltage. When you enter open-circuit voltage at stc in V, the calculator uses it in the engineering formula to compute the output

How should I interpret the result maximum dc string voltage?

The calculator outputs maximum dc string voltage in V. The result is computed directly from the input values using the defined engineering formula

What units should I use for the inputs?

Enter each value in the units shown next to the input field: Open-Circuit Voltage at STC (V), Temperature Coefficient of Voc (V/°C), Record Low Ambient Temperature (°C), STC Temperature (°C). Make sure all inputs use the specified units for consistent results

What assumptions does this calculator use?

This calculator uses automatically validated engineering formulas. Results are approximate and should be validated against site-specific conditions, applicable codes, and professional engineering judgment

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