Data Centre Electrical Hotspot: Overload or Loose Connection? Malaysia

An electrical hotspot inside a data centre may be caused by high load, phase imbalance, a loose connection, damaged contact, poor ventilation or failing equipment.

A thermal camera can locate the abnormal heat, but the thermal image alone may not identify the cause.

Technicians should compare the temperature pattern with electrical current, equipment load, similar components and previous inspection records.

A structured data centre electrical hotspot investigation helps Malaysian facility teams decide whether the condition involves normal loading, abnormal resistance or a developing equipment fault.

Where Are Electrical Hotspots Commonly Found?

Potential locations include:

• Main switchgear

• Circuit breakers

• Busbar connections

• Transformer terminals

• UPS input and output terminals

• UPS bypass connections

• Battery terminals

• Automatic transfer switches

• Generator connections

• Distribution boards

• Rack PDUs

• Plugs and sockets

• Cable joints

• Neutral connections

• Power-supply modules

• Cooling-equipment electrical panels

Inspection must be performed only by authorised personnel following the facility’s electrical-safety procedure.

Why Do Electrical Components Become Hot?

Common causes include:

• High electrical load

• Phase imbalance

• Loose connection

• Increased contact resistance

• Corrosion

• Oxidation

• Damaged conductor

• Incorrect cable size

• Poor crimping

• Worn breaker contact

• Overloaded neutral

• Harmonic current

• Inadequate ventilation

• High ambient temperature

• Failed cooling fan

• Internal equipment fault

• Incorrect installation torque

A hot component may have more than one contributing factor.

Hotspot Warning Signs

Look for:

• Discolouration

• Burn marks

• Melted insulation

• Abnormal smell

• Cracked connector

• Loose terminal

• Buzzing

• Arcing evidence

• Repeated breaker operation

• Voltage drop

• Uneven phase current

• High neutral current

• Equipment alarm

• Increasing temperature trend

Do not touch or tighten an energised hot connection unless the approved procedure specifically permits the work.

Essential Investigation Tools

Depending on the authorised scope, technicians may require:

• Noyafa NF-522 Thermal Camera

• AC/DC clamp meter

• Digital multimeter

• Power quality analyzer

• Infrared thermometer

• Contact-temperature probe

• Insulation resistance tester

• Earth resistance tester

• Torque tools for isolated work

• Temperature data logger

• Suitable personal protective equipment

All instruments and accessories must have safety ratings suitable for the electrical environment.

Thermal Camera Versus Clamp Meter

Use both instruments for stronger diagnosis.

Overload Versus Loose Connection

A high-load component and a loose connection may both appear hot.

The surrounding pattern provides useful clues.

Possible Overload Pattern

An overload may produce:

• Heating across the conductor

• Similar heating at several connected components

• High measured current

• Temperature corresponding with load

• Several phases or devices affected

• Temperature reducing when load decreases

Possible Loose-Connection Pattern

A loose or high-resistance connection may produce:

• Concentrated heating at one terminal

• One phase hotter than similar phases

• Hot connector with cooler cable nearby

• Temperature disproportionate to current

• Discolouration at the connection

• Increasing heat over time

• Intermittent voltage or equipment problems

These are indicators, not final proof.

Step 1: Confirm Safety and Authorisation

Before inspection:

• Review the electrical single-line diagram

• Confirm equipment identification

• Follow arc-flash and electrical-safety requirements

• Wear required PPE

• Maintain safe working distance

• Use suitable instruments

• Confirm permitted panel access

• Keep unauthorised personnel away

• Follow site communication procedures

Do not remove covers or open live equipment without authorisation.

Step 2: Record the Operating Condition

Record:

• Equipment load

• UPS operating mode

• Generator or utility supply

• Cooling condition

• Ambient temperature

• Time

• Active alarms

• Maintenance activity

Thermal results taken at low load may not reveal a condition that appears during normal or peak operation.

Step 3: Perform a General Thermal Scan

Begin with a wider scan of:

• Entire panel

• Similar breakers

• Three phases

• Cable entries

• Ventilation areas

• Equipment exterior

Then examine suspicious components more closely.

The Noyafa NF-522 Thermal Camera can support practical hotspot detection across electrical and mechanical equipment.

Step 4: Compare Similar Components

Compare:

• Phase L1, L2 and L3

• Similar circuit breakers

• Parallel cables

• Identical UPS modules

• Similar battery connections

• Comparable rack PDUs

• Current and previous thermal images

Comparison is usually more useful than judging one temperature in isolation.

Step 5: Measure Electrical Current

Qualified technicians may use a clamp meter to measure:

• Individual phase current

• Neutral current

• UPS input current

• UPS output current

• Generator current

• Rack PDU current

• Branch-circuit current

Record the current together with the thermal image.

Without load information, it is difficult to interpret the temperature correctly.

Step 6: Check Phase Balance

Compare the currents on all phases.

Uneven phase loading may cause:

• One conductor running hotter

• Reduced available capacity

• Higher neutral current

• UPS or generator imbalance

• Uneven transformer heating

• Protection problems

Do not redistribute critical loads without an approved plan.

Step 7: Check Neutral Current

High neutral current may be associated with:

• Unbalanced single-phase loads

• Harmonics

• Non-linear electronic loads

• Incorrect wiring

• Shared-neutral problems

A power quality analyzer may be required when the cause cannot be established with a clamp meter.

Step 8: Compare Temperature With Current

Possible findings include:

Actual severity must be classified according to the facility procedure and equipment requirements.

Step 9: Check the Temperature Pattern

Inspect whether heat is concentrated at:

• Terminal

• Cable

• Breaker body

• Busbar

• Fuse

• Connector

• Joint

• Power-supply module

• Ventilation outlet

The location of maximum heating may help narrow the cause.

Step 10: Consider Thermal Emissivity

Different surfaces emit and reflect infrared energy differently.

Shiny metal may produce misleading readings because of:

• Low emissivity

• Reflected heat

• Viewing angle

• Nearby hot objects

Where permitted, use a suitable high-emissivity reference point or another approved measurement method.

Do not apply tape or labels to energised equipment without authorisation.

Step 11: Check Reflections

Before classifying a hotspot:

• Change the viewing angle

• Compare nearby surfaces

• Check for reflected personnel or equipment

• Observe whether the apparent hotspot moves

• Confirm using another method

A reflected thermal image does not represent actual component temperature.

Step 12: Check Ambient Temperature

Record the surrounding air temperature.

The same component temperature may have different significance under:

• Cool server-room conditions

• Hot generator-room conditions

• Restricted enclosure ventilation

• High outdoor ambient temperature

Temperature difference compared with similar components can provide useful context.

Step 13: Inspect Ventilation

Check for:

• Blocked ventilation openings

• Dirty filters

• Failed fan

• Dust accumulation

• Closed panel opening

• Obstructed exhaust

• High room temperature

• Cooling-unit problem

An entire panel may become warm because its cooling or ventilation is inadequate.

Step 14: Review Equipment Logs

Check:

• UPS alarms

• Breaker events

• Generator logs

• Automatic transfer switch events

• Power quality records

• Building-management alarms

• Rack PDU records

• Cooling-system alarms

The hotspot may correspond with a specific operating condition.

Step 15: Review Previous Thermal Images

Compare:

• Same component

• Similar load

• Similar ambient temperature

• Same camera angle

• Same operating mode

A gradual temperature increase can be more important than one isolated reading.

Step 16: Use Power Quality Monitoring When Required

A power quality analyzer may be needed to investigate:

• Harmonics

• Voltage imbalance

• Current imbalance

• Voltage sag

• High neutral current

• Repeated UPS transfer

• Intermittent overheating

• Unexplained breaker trip

A spot measurement may miss a short event.

Step 17: Inspect During an Approved Shutdown

When the equipment is safely isolated and proven de-energised, qualified personnel may inspect:

• Terminal tightness

• Contact condition

• Discolouration

• Corrosion

• Cable damage

• Crimp quality

• Breaker condition

• Busbar joint

• Insulation condition

Use the equipment manufacturer’s torque requirements.

Do not tighten every terminal blindly. Incorrect torque can also damage the connection.

Step 18: Check Cable Size and Installation

Review:

• Cable size

• Current capacity

• Installation method

• Ambient-temperature correction

• Cable grouping

• Termination suitability

• Conductor material

• Lug compatibility

• Signs of mechanical strain

An undersized or incorrectly terminated cable may heat even when the equipment itself is functioning.

Step 19: Inspect Battery Connections

UPS battery hotspots may result from:

• Loose terminal

• Corrosion

• High-resistance interconnection

• Damaged cable

• Battery defect

• Charging imbalance

Compare all similar battery connections under the same operating condition.

Battery inspection must follow the manufacturer’s safety procedure.

Step 20: Inspect Rack PDUs and Plugs

Check:

• Outlet loading

• Plug fit

• Cable condition

• Adapter use

• PDU load

• Loose connection

• Discolouration

• Localised heat

• Redundant power-feed balance

One overloaded or damaged rack PDU may affect critical IT equipment.

Example: One Phase Terminal Is Hot

Possible causes include:

• Loose connection

• Corrosion

• Damaged lug

• Higher phase current

• Worn breaker contact

• Incorrect torque

Measure current on all phases and compare the thermal pattern.

Example: All Three Phase Cables Are Hot

Possible causes include:

• High total load

• Undersized conductors

• High ambient temperature

• Cable grouping

• Poor ventilation

• Harmonic loading

Review current, cable rating and operating conditions.

Example: Breaker Body Is Hot but Terminals Are Cooler

Possible causes include:

• High load

• Internal contact deterioration

• Breaker defect

• Poor ventilation

• Equipment age

The responsible electrical specialist should assess the breaker according to the manufacturer’s recommendations.

Example: Neutral Cable Is Hotter Than Phase Cables

Possible causes include:

• High neutral current

• Load imbalance

• Harmonics

• Loose neutral connection

• Incorrect conductor size

Measure neutral current and consider power-quality analysis.

Example: UPS Terminal Is Hot During Battery Charging

Check:

• Charging current

• Connection condition

• Cable size

• Terminal torque

• UPS alarm

• Comparison with other terminals

• Previous thermal images

Example: Rack PDU Plug Is Hot

Check:

• Equipment load

• Plug condition

• Outlet contact

• Cable damage

• Adapter use

• PDU rating

• Local ventilation

Transfer of critical load must follow an approved procedure.

Hotspot Priority Assessment

Consider:

• Temperature difference

• Electrical load

• Equipment criticality

• Rate of temperature increase

• Evidence of damage

• Fault history

• Redundancy

• Consequence of failure

• Manufacturer limits

• Site maintenance criteria

Do not classify severity from temperature alone.

Common Thermal Inspection Mistakes

Avoid:

• Scanning equipment at very low load

• Recording no current measurement

• Ignoring ambient temperature

• Comparing unrelated components

• Using incorrect emissivity

• Mistaking reflection for a hotspot

• Saving images without equipment identification

• Inspecting from an unsafe position

• Assuming every hotspot is an overload

• Tightening live terminals

• Closing the finding without retesting

What Should the Inspection Report Include?

Record:

• Asset and equipment name

• Panel or circuit

• Phase

• Exact hotspot location

• Thermal image

• Visual image

• Maximum observed temperature

• Reference temperature

• Ambient temperature

• Electrical current

• Equipment load

• Emissivity setting

• Inspection distance

• Suspected cause

• Priority

• Corrective action

• Retest result

Recommended Electrical Inspection Kit

A practical kit may include:

• Noyafa NF-522 Thermal Camera

• AC/DC clamp meter

• Digital multimeter

• Power quality analyzer

• Insulation resistance tester

• Earth resistance tester

• Non-contact voltage detector

• Suitable temperature probe

• Approved PPE

• Inspection and documentation accessories

Verify the Corrective Action

After repair:

1. Restore equipment using the approved procedure.

2. Allow it to operate under representative load.

3. Repeat the thermal scan.

4. Repeat phase and neutral current measurements.

5. Compare with similar components.

6. Check equipment alarms.

7. Confirm that temperature is stable.

8. Record the final thermal and visual images.

9. Update the maintenance record.

10. Schedule follow-up inspection where required.

A Thermal Image Finds the Heat—Measurements Explain It

A hot connection is not automatically an overload, and high current does not automatically explain a concentrated terminal hotspot.

The strongest investigation combines:

• Thermal pattern

• Phase and neutral current

• Equipment load

• Ambient temperature

• Similar-component comparison

• Previous inspection records

• Isolated physical inspection where required

Using a thermal camera together with a clamp meter or power quality analyzer helps data-centre teams distinguish load-related heating from loose, damaged or high-resistance electrical connections.

Contact MTM Precision

MTM Precision Sdn. Bhd.

Showroom & Service Centre

No. 29-1 & 29-2, Jalan Bandar 18,
Pusat Bandar Puchong,
47160 Puchong, Selangor, Malaysia

🌐 Website: www.mtmpre.com.my
📧 Email: mtmpre@yahoo.com
📱 WhatsApp: +6016-660 7346