How do I size a cable in India as per IS standards?

Cable sizing in India follows IS 694 (LT PVC cables) and IS 1554 (armoured cables). A cable must satisfy two criteria: (1) Current carrying capacity — the cable must handle the full load current without overheating. (2) Voltage drop — must not exceed 2.5% (IS recommended) or 5% (maximum) of supply voltage. The minimum cable cross-section for voltage drop is calculated as: Area (mm²) = √3 × ρ × I × L / ΔV for 3-phase, where ρ = 0.0175 for copper or 0.028 for aluminium. Use the IndiaMeters Cable Size Calculator for instant results including derating for multicore and armoured cables.

What is COP in air conditioning and what is a good COP value?

COP (Coefficient of Performance) measures the efficiency of an air conditioner. COP = Cooling output (kW) / Power input (kW). A good split AC has a COP of 3.0–4.5, meaning it delivers 3 to 4.5 kW of cooling for every 1 kW of electricity consumed. Inverter ACs can achieve COP up to 5.5. Central chillers range from 4.0 to 6.5. BEE 5-star rated ACs in India have an ISEER (Indian Seasonal EER) of 5.00 or above.

Free Engineering Calculator — Pressure, Electrical, Cable Size, 4-20mA

Free online calculators for electrical engineers, instrumentation technicians, and industrial professionals in India. Convert pressure units (bar, PSI, kPa), calculate 3-phase power and full load current, size copper and aluminium cables per IS 694 / IS 1554 standards, convert 4–20mA signals to engineering units, and more — all in one place.

🛒 Shop test & measuring instruments at IndiaMeters.in →

⚡Electrical

ΩOhm's Law

🔌Cable Size

↕Transformer

📐Pressure

📶4–20mA

🌡Temperature

~Freq/Vib

🔄Torque

☀Solar

🌊HVAC

💡Illuminance

📏Length & Area

💧Flow

📡dBm/mW

🧲Gauss/Tesla

Electrical Power Calculator — kW, kVA, HP, Energy & 3-Phase

Power

3-Phase

Energy

Power converter

Value

Convert to

0.001kW

Need a power meter or clamp meter?
HTC DM98 TRMS Multimeter → | HTC 21-S Smart Clamp Meter →

3-phase power calculator

Voltage (L-L)V

CurrentA

Power factor

Active (kW)

—

Apparent (kVA)

—

Reactive (kVAR)

—

Full load current (FLC)

Motor power

Voltage (L-L)V

Power factor

Efficiency

—A (full load current)

Star ↔ delta

Line voltageV

Line currentA

Star phase V

—

Star phase I

—

Delta phase V

—

Delta phase I

—

Energy converter

Value

Convert to

3,600,000J

Energy cost calculator

PowerkW

Hours/dayh

Tariff₹/kWh

Daily cost

—

Monthly cost

—

Need an energy meter or power analyser?
Satec PM130EH Plus Multifunction Energy Meter → | Kusam Meco KM-2100 Power Quality Analyser →

Need power measurement instruments?
Kusam Meco KM-2709 TRMS Power Clamp Meter → | KM-2100 Power Quality Analyser →

Who uses this calculator?+

Electrical engineers
Panel builders
Industrial electricians
Energy auditors
Maintenance technicians

Temperature Converter & RTD Calculator — °C, °F, K, PT100, Thermocouple mV

Temperature converter

Value

Convert to

77°F

PT100 / PT1000 RTD resistance

Temperature°C

PT100

109.73 Ω

PT1000

1097.3 Ω

Thermocouple mV output

Temperature°C

TC type

4.096mV

Need temperature measurement instruments?
HTC Scan II IR Thermometer → | Innova TT-201 Temperature Transmitter → | Kusam Meco IRL-866 IR Thermometer (-50 to 2250°C) →

Who uses this calculator?+

Instrumentation engineers
Process engineers
HVAC technicians
Calibration engineers
Quality control technicians

Pressure Unit Converter — bar, PSI, kPa, atm, mmHg, inH₂O

Pressure converter

Value

Convert to

14.504PSI

Need pressure measurement instruments?
Innova TT-201 Temperature & Pressure Transmitter → | Innova RTR-02 Resistance Transducer → | Innova CAL45-AV Process Calibrator →

Who uses this calculator?+

Instrumentation engineers
Process engineers
Mechanical engineers
Oil & gas technicians
Chemical plant operators

4-20mA Signal Calculator — Loop Current to Engineering Units

4–20mA → process value

Range min

Range max

mA valuemA

50%= 50.000 units

Process value → mA

Range min

Range max

Process value

12.00mA

Need a 4–20mA calibrator or loop tester?
Innova CAL45-AV mA & mV Source → | HTC CC-05 Multifunction Calibrator →

Who uses this calculator?+

Instrumentation engineers
Control & automation engineers
Calibration technicians
DCS/SCADA engineers
Process technicians

Ohm's Law Calculator — Voltage, Current, Resistance & Power

Ohm's law — enter any 2 values

Voltage (V)

Current (I)

Resistance (R)

Power (P)

Voltage

—

Current

—

Resistance

—

Power

—

Need a multimeter or digital meter?
HTC DM98 TRMS Multimeter → | HTC DM-15S Smart Multimeter → | Kusam Meco KM788BT Bluetooth Multimeter →

Who uses this calculator?+

Electrical engineers
Electronics technicians
Electrical students
Panel builders
Field maintenance engineers

Cable Size Calculator India — IS 694 / IS 1554 Copper & Aluminium

Cable parameters

Load currentA

Cable lengthm (one way)

System

Max volt drop

Conductor

Construction

Armouring

Cores

Installation

Recommended cable

—mm²

Current capacity reference (IS 694 / IS 1554)

Cu rigid

Cu flexible

Al rigid

mm²	Conduit	Tray	Buried
1.5	13A	15A	18A
2.5	18A	22A	25A
4	24A	30A	35A
6	31A	38A	45A
10	42A	52A	60A
16	56A	70A	80A
25	73A	92A	105A
35	89A	112A	128A
50	108A	136A	155A
70	136A	174A	195A
95	164A	210A	235A
120	188A	242A	270A

mm²	Conduit	Open air	Note
0.5	3A	4A	Light duty
0.75	6A	7A	Light duty
1.0	10A	11A	—
1.5	13A	15A	—
2.5	18A	21A	—
4	24A	28A	—
6	31A	36A	—
10	42A	50A	—
16	54A	66A	—

Flexible cables not recommended above 16mm².

mm²	Conduit	Tray	Buried
4	18A	22A	26A
6	23A	29A	34A
10	32A	40A	46A
16	43A	54A	62A
25	57A	72A	82A
35	70A	88A	100A
50	84A	106A	120A
70	107A	136A	153A
95	129A	164A	185A
120	149A	188A	212A
150	170A	216A	243A
185	194A	245A	276A

Al not available below 4mm². Min. 16mm² recommended per IS 8130.

Need instruments to verify your cable installation?
Sonel MIC 5001 Insulation Tester → | HTC DM98 TRMS Multimeter →

Who uses this calculator?+

Electrical engineers
Industrial electricians
Panel builders
Maintenance technicians
Instrumentation engineers

Frequency, RPM & Vibration Calculator — Hz, RPM, rad/s, ISO 10816

Freq / RPM

Vibration

Frequency & RPM converter

Value

Convert to

3000RPM

Motor synchronous speed

FrequencyHz

Poles

1500RPM (synchronous)

Vibration converter

Value

FrequencyHz

Convert to

—

ISO 10816 severity guide

≤ 0.28 mm/sGood

0.28 – 1.12 mm/sSatisfactory

1.12 – 4.5 mm/sUnsatisfactory

4.5 – 11.2 mm/sUnacceptable

> 11.2 mm/sDanger

Need vibration & speed measurement instruments?
HTC VB-8205 Digital Vibration Meter → | HTC MC-45 Digital Motor Checker → | Kusam Meco KM-2709 Power Clamp Meter →

Who uses this calculator?+

Motor & drive engineers
Maintenance engineers
VFD commissioning engineers
Predictive maintenance teams
Rotating equipment engineers

Illuminance Converter — Lux, Foot-candle, Phot

Illuminance converter

Value

Convert to

92.9fc

Typical illuminance reference

Direct sunlight100,000 lux

Office lighting300–500 lux

Corridor100 lux

Emergency exit1 lux

Need a lux meter?
HTC LX-108L LED Lux Meter → | HTC LX-104 Professional Lux Meter →

Who uses this calculator?+

Electrical engineers
Lighting designers
Facility managers
Safety officers
Architects & building contractors

Torque Converter & Power to Torque Calculator — N·m, kgf·m, lb·ft

Torque converter

Value

Convert to

0.1020kgf·m

Power → torque

PowerkW

SpeedRPM

6.58N·m

Need motor testing instruments?
HTC MC-45 Digital Motor Checker → | HTC 21-S 600A Smart Clamp Meter →

Who uses this calculator?+

Mechanical engineers
Motor & drive engineers
Maintenance technicians
Rotating equipment engineers
Manufacturing engineers

Length, Area & Volume Calculator — Metric, Imperial, Shape Area

Length

Area

Volume

Length / distance converter

Value

Convert to

1000mm

Need a laser distance meter?
HTC LD-100 Laser Distance Meter →

Area converter

Value

Convert to

10.764ft²

Shape area calculator

Shape

Length (a)m

Width (b)m

Area

50.00 m²

Perimeter

30.00 m

Volume converter

Value

Convert to

1000L

Tank / vessel volume calculator

Shape

Dim Am

Dim Bm

Dim Cm (height/length)

Volume (m³)

—

Volume (Litres)

—

Who uses this calculator?+

Civil engineers
Mechanical engineers
Surveyors
Construction contractors
Facility managers

Flow Rate Converter — m³/h, L/min, GPM, CFM

Flow rate converter

Value

Convert to

16.667L/min

Need flow measurement instruments?
Innova CAL45-AV mA Source (for flow transmitter calibration) → | HTC CC-05 Multifunction Process Calibrator →

Who uses this calculator?+

Process engineers
Chemical engineers
Utilities engineers
Instrumentation technicians
Water treatment operators

dBm to mW / Watt Converter — RF Power Conversion

dBm ↔ mW / W converter

Value

in mW

1.000 mW

in dBm

0.000 dBm

dB reference levels

30 dBm= 1 W

0 dBm= 1 mW

−10 dBm= 0.1 mW

−30 dBm= 1 µW

Need RF & signal measurement instruments?
Siglent SSA3032X 3.2GHz Spectrum Analyser →

Who uses this calculator?+

RF & telecom engineers
Network engineers
Electronics engineers
Signal integrity engineers
Test & measurement engineers

Gauss to Tesla Converter — Magnetic Flux Density Calculator

Magnetic flux density converter

Value

Convert to

10000G

Magnetic field reference levels

Earth's magnetic field25–65 µT

Neodymium (NdFeB) magnet1–1.4 T

MRI machine1.5–3 T

Transformer core (silicon steel)1.5–1.7 T

Motor / generator air gap0.6–1.0 T

ICNIRP public limit (50 Hz)200 µT

Need a Gauss meter or EMF meter?
HTC GD-801 4-Gas Detector → | Kusam Meco KM-2100 Power Quality Analyser → | Browse all test instruments →

Who uses this calculator?+

R&D engineers
Electrical engineers
Motor & transformer designers
Quality control engineers
Test & measurement professionals

Transformer Calculator — Turns Ratio, KVA Sizing, Regulation, Efficiency

Turns ratio

KVA sizing

Regulation

Turns ratio calculator

Primary VV

Secondary VV

Turns ratio (Np:Ns)

—

Voltage ratio

—

Current & turns from KVA

KVA ratingkVA

Primary FLC

—

Secondary FLC

—

If Np = 1000 turns

—

Current ratio Is:Ip

—

TTR test — measured vs nameplate

Nameplate ratio

Measured ratio

—% deviation

Need a Transformer Turns Ratio (TTR) tester?
Uma ATRI-3 Automatic TTR Tester → | ELTEL TRM-100 TTR Tester →

Transformer KVA sizing

Total loadkW

Power factor

Demand factor(0–1)

Future growth%

Required KVA

—

Recommended size

—

Standard transformer KVA ratings (IS 1180)

Single phase1, 2, 5, 10, 25, 63, 100, 250 kVA

Three phase (dist.)16, 25, 63, 100, 160, 250, 400, 630 kVA

Three phase (power)1, 1.6, 2, 2.5, 4, 6.3, 10, 16, 25 MVA

Full load current (primary & secondary)

KVA ratingkVA

Primary VV

Secondary VV

Phases

Primary FLC

—

Secondary FLC

—

Need power measurement instruments?
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Voltage regulation %

No-load voltageV

Full-load voltageV

—% regulation

Acceptable: < 5% for distribution transformers (IS 1180). < 2% for precision applications.

Transformer efficiency %

Output powerkW

Iron losses (Pi)kW

Copper losses (Pc)kW

Efficiency

—

Total losses

—

Short circuit current

KVA ratingkVA

Secondary VV

Impedance %%

Phases

Full load current

—

Short circuit current

—

Use Isc to select MCCBs, fuses, and busbar ratings on the secondary side.

Need transformer test equipment?
OTS-100 Oil BDV Test Set → | Sonel MIC 5001 Insulation Tester →

Who uses this calculator?+

Electrical engineers
Transformer commissioning engineers
Substation engineers
Panel builders
Maintenance engineers

Solar System Calculator — Panel Sizing, Battery Backup, Payback Period

Panel sizing

Battery

Savings

Solar panel sizing

Daily usagekWh/day

Peak sun hourshrs/day

System losses% (dust, wiring)

Panel wattageWp each

System size needed

—

No. of panels

—

Inverter & charge controller sizing

Total AC loadW

Safety margin%

Panel arrayWp total

Battery voltage

Inverter size

—

Charge controller

—

MPPT input I

—

Solar string sizing

Panel VocV

Panel IscA

Target string VV

Target array IA

Panels in series

—

Strings in parallel

—

Total Voc

—

Total Isc

—

Solar instruments for installation & testing:
HATCO DM-4010 Solar Multimeter (2000VDC) →
HATCO CM-4020 Solar Clamp Meter →

Battery backup sizing

LoadW

Backup neededhours

Battery voltage

DoD limit

Inverter eff.%

Required Ah

—

Required kWh

—

Battery configuration

Battery unit AhAh

Battery unit VV

System voltage

Required AhAh

Batteries in series

—

Strings in parallel

—

Total batteries

—

Battery type comparison

Lead-acid (FLA)DoD 50%, 300–500 cycles

VRLA / AGMDoD 50–60%, 500–800 cycles

Lithium-ion (NMC)DoD 80%, 1000–2000 cycles

LiFePO4DoD 100%, 3000–6000 cycles

Monthly savings calculator

System sizekWp

Peak sun hourshrs/day

System efficiency%

Electricity tariff₹/kWh

System cost₹

Annual tariff hike%/year

Daily generation

—

Monthly generation

—

Monthly savings

—

Annual savings

—

Payback & ROI

Simple payback

—

25-year savings

—

CO₂ offset (25 years)

—

Assumes 0.7% annual panel degradation. Subsidy benefits not included — check PM Surya Ghar scheme for residential rooftop solar.

Solar testing instruments:
HTC Scan II IR Thermometer (hotspot detection) →
Sonel MIC 5001 Insulation Tester (string testing) →

Who uses this calculator?+

Solar EPC contractors
Electrical engineers
Energy consultants
Rooftop solar installers
Home owners & facility managers

HVAC Calculator — Cooling Load, BTU, COP, EER, Duct Sizing

Cooling load

Unit convert

Airflow & duct

Efficiency

Room cooling load calculator

Room aream²

Ceiling heightm

Occupants

Sun exposure

Location

Required BTU/hr

—

Tonnes of refrig.

—

Recommended AC

—

Superheat & subcooling check

Suction line temp°C

Suction pressurebar g

Liquid line temp°C

High side pressurebar g

Refrigerant

Superheat

—

Subcooling

—

Target superheat: 5–10°C. Target subcooling: 4–8°C. Values outside range indicate incorrect refrigerant charge.

HVAC testing instruments:
HTC Scan II IR Thermometer → | Innova TT-201 Temperature Transmitter →

AC capacity unit converter

Value

Convert to

12000BTU/hr

Quick reference

1 TR= 3517 W = 12,000 BTU/hr

1 kW cooling= 0.2843 TR = 3412 BTU/hr

1.5 TR split AC= 18,000 BTU/hr ≈ 1.76 kW input

2.0 TR split AC= 24,000 BTU/hr ≈ 2.35 kW input

1 kcal/hr= 1.163 W = 3.97 BTU/hr

Temperature converter

Value

Convert to

77°F

Required airflow (CMH / CFM)

Room aream²

Ceiling heightm

Air changes/hr

Airflow (CMH)

—

Airflow (CFM)

—

Round duct sizing

AirflowCFM

Max velocity

Duct diameter

—

Actual velocity

—

Rectangular duct equivalent

Round dia.mm

Duct width (a)mm

—mm height (b)

COP calculator

Cooling outputkW

Power inputkW

COP

—

EER

—

Good split AC: COP 3.0–4.5. Inverter AC: up to 5.5. Central chiller: 4.0–6.5.

EER & ISEER (BEE star rating)

Cooling capacityBTU/hr

Power inputW

EER

—

BEE star rating

—

5-star (ISEER)≥ 5.00

4-star4.50–4.99

3-star3.99–4.49

2-star3.49–3.98

Running cost calculator

AC capacityTR

EER

Hours/day

Tariff₹/kWh

Daily cost

—

Monthly cost

—

HVAC measurement instruments:
Innova TT-201 Temperature Transmitter → | HTC Scan II IR Thermometer →

Who uses this calculator?+

HVAC engineers
Mechanical engineers
Building services engineers
AC installation technicians
Facility managers

Frequently asked questions

How do I convert bar to PSI?+

To convert bar to PSI, multiply by 14.5038. For example, 1 bar = 14.504 PSI, 10 bar = 145.04 PSI. To convert PSI back to bar, divide by 14.5038. Use the Pressure tab above for instant conversion between bar, PSI, kPa, atm, mmHg, mbar and inH₂O.

What is a 4-20mA signal and how is it calculated?+

A 4-20mA current loop is the standard for transmitting sensor readings in industrial plants. 4mA = minimum range (0%), 20mA = maximum range (100%). Formula: PV = Range Min + ((mA – 4) / 16) × (Range Max – Range Min). Example: 12mA on a 0–100 bar transmitter = 50 bar. The 4–20mA tab above also does the reverse — process value back to mA.

How do I size a cable in India as per IS 694?+

Cable sizing in India (IS 694 / IS 1554) uses two criteria: (1) Current carrying capacity — the cable must handle full load current continuously. (2) Voltage drop — must not exceed 2.5% (IS recommended) or 5% (max). Minimum area for volt drop: Area (mm²) = √3 × ρ × I × L / ΔV for 3-phase (ρ = 0.0175 for copper, 0.028 for aluminium). Use the Cable Size tab above which handles copper, aluminium, armoured, multicore and all installation methods automatically.

What is the formula for 3-phase power (kW, kVA, kVAR)?+

kVA (apparent) = √3 × V(L-L) × I / 1000 • kW (active) = kVA × Power Factor • kVAR (reactive) = kVA × √(1 – PF²). Motor full load current (FLC) = kW × 1000 / (√3 × V × PF × Efficiency). In India, standard 3-phase supply is 415V L-L at 50 Hz. Use the Electrical → 3-Phase tab above.

How many solar panels do I need for my home in India?+

System size (kWp) = Daily consumption (kWh) / (Peak sun hours × (1 – losses%)). Most Indian cities get 4.5–5.5 peak sun hours/day. With 20% system losses and 400Wp panels, a home using 10 kWh/day needs approx. 2.5 kWp = 7 panels. The Solar → Panel Sizing tab above also calculates inverter size, charge controller, battery backup, monthly savings in ₹, payback period, and 25-year ROI.

What is COP in air conditioning and what is a good value?+

COP (Coefficient of Performance) = Cooling output (kW) / Power input (kW). A good split AC has COP 3.0–4.5. Inverter ACs reach up to 5.5. Central chillers: 4.0–6.5. BEE 5-star ACs in India have an ISEER ≥ 5.00. A higher COP means lower electricity bills. Use the HVAC → Efficiency tab to calculate COP, EER, BEE star rating, and monthly running cost in ₹.

What is the resistance of a PT100 RTD at different temperatures?+

PT100 has exactly 100Ω at 0°C and increases with temperature: R(T) = 100 × (1 + 0.003851T – 0.000000599T²). Key values: −50°C = 80.31Ω, 0°C = 100Ω, 25°C = 109.73Ω, 100°C = 138.51Ω, 200°C = 175.86Ω. PT1000 is identical but 10× the resistance (1000Ω at 0°C). Use the Temperature tab above to calculate PT100/PT1000 resistance for any temperature.

Share this toolkit with your team:

IndiaMeters Engineering Toolkit provides free online calculators including: pressure converter (bar, PSI, kPa, atm, mmHg) • 4–20mA to engineering units calculator • 3-phase power calculator (kW, kVA, kVAR) • motor full load current (FLC) calculator • cable size estimator per IS 694 / IS 1554 (copper & aluminium) • PT100 / PT1000 RTD resistance calculator • Ohm's law calculator • vibration converter (ISO 10816) • illuminance converter (Lux, foot-candle) • frequency & RPM converter • torque converter • energy cost calculator (₹/kWh).

Looking for test & measuring instruments? Visit IndiaMeters.in — India's trusted source for Hioki, Fluke, Kusam Meco, HTC, Innova, and Masibus instruments at the best prices.

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IndiaMeters Toolkit

Electrical Power Calculator — kW, kVA, HP, Energy & 3-Phase

Temperature Converter & RTD Calculator — °C, °F, K, PT100, Thermocouple mV

Pressure Unit Converter — bar, PSI, kPa, atm, mmHg, inH₂O

4-20mA Signal Calculator — Loop Current to Engineering Units

Ohm's Law Calculator — Voltage, Current, Resistance & Power

Cable Size Calculator India — IS 694 / IS 1554 Copper & Aluminium

Frequency, RPM & Vibration Calculator — Hz, RPM, rad/s, ISO 10816

Illuminance Converter — Lux, Foot-candle, Phot

Torque Converter & Power to Torque Calculator — N·m, kgf·m, lb·ft

Length, Area & Volume Calculator — Metric, Imperial, Shape Area

Flow Rate Converter — m³/h, L/min, GPM, CFM

dBm to mW / Watt Converter — RF Power Conversion

Gauss to Tesla Converter — Magnetic Flux Density Calculator

Transformer Calculator — Turns Ratio, KVA Sizing, Regulation, Efficiency

Solar System Calculator — Panel Sizing, Battery Backup, Payback Period

HVAC Calculator — Cooling Load, BTU, COP, EER, Duct Sizing