What you will see
- A new or noticeably louder buzzing sound.
- Crackling or popping from the board.
- Discoloured plastic, scorch marks or a burning smell.
- Intermittent loss of power alongside the sound.
Why it happens
Some electrical equipment produces operational hum. Schneider Electric explains that vibration and resonating components can contribute to noise, and that sound alone does not prove a breaker has failed.
However, unusual noise accompanied by discolouration or other signs of overheating needs prompt assessment. Electrical Safety Foundation guidance identifies crackling, buzzing and discolouration among electrical warning signs.
A customer recording cannot establish whether a connection is loose, a component is damaged or a normal sound has become amplified. The correct next step is an inspection appropriate to the symptoms, not tightening something through an open cover.
Describe what changed. A noise that has recently become louder, begins with a specific machine or is accompanied by a smell provides useful information. Do not remain beside the board waiting for the event to happen again.
Hum or warning sign?
Steady, familiar hum
Some equipment hums in normal use. Note if it changes.
New buzz, crackle, smell or scorching
Signs of possible overheating. Stop and get it assessed promptly.
- 01Keep people away from the board
- 02Call from a safe place
- 03Describe what changed and when
- 04Share existing photos only
Do not remove covers, tighten terminals, spray anything or keep it running to demonstrate the noise.
Safety first: the first five minutes
- Smoke, flames, sparks, hissing or a swollen battery: leave the room, close the door behind you, get everyone out, and call Rescue 1122. Tell them there is a solar system and, if you have one, a lithium battery.
- Smell only, no smoke: if the switches are away from the heat and smoke, switch off in your manual's order, often the AC breaker, then the DC isolator, then the battery breaker.
- Do not open the inverter, battery or distribution board (DB), touch cables, or use water on electrical equipment.
- Remember the panels keep producing DC in daylight, and an isolated battery still holds energy. Switching off makes the system safer, not dead.
What a burning smell from inverter or solar wiring means
Electrical parts smell when they get hot enough to cook their plastic, insulation or coatings. In a solar system that heat comes from one of four places:
- A loose or high-resistance connection: a terminal in the DB, a breaker screw, a battery cable lug or an MC4 joint on the roof.
- An overloaded or undersized part: cable too thin for the current, a breaker or isolator not rated for the job, or an inverter running beyond its limit for hours.
- A failing component inside the inverter or battery: a fan, capacitor, relay or circuit board, or a battery cell.
- Something outside the system: a socket or plug on a heavy appliance, an overheating AC wire, or burning rubbish nearby.
The smell itself does not tell you which. Where it is strongest, when it happens, and what the app shows do.
Burning smell
Switch off
By the manual's sequence
Keep clear
Do not open boards
Call
An engineer at once
Quick-check table: inverter smell, smoke and solar wire burning
| Symptom | Likely cause | Safe owner check | Call an engineer if... |
|---|---|---|---|
| Hot plastic or "fishy" electrical smell near the inverter | Overheating component, failing fan, or terminal heating | Read the screen and app for temperature or fan alarms; note the load | Always |
| Smoke from solar inverter vents or casing | Internal failure | None: get out and call Rescue 1122 | Always |
| Smell at the DB or breaker panel | Loose terminal, undersized cable, wrong breaker | Look for discoloured breakers from a distance; note any tripping | Always |
| Smell on the roof or near the DC isolator | MC4 joint, damaged DC cable, isolator terminal | Photograph from a safe distance; check string data in the app | Always; see MC4 connector burnt |
| Sweet, chemical or solvent smell near the battery | Battery overheating or venting | None: keep away, ventilate only if safe, call Rescue 1122 if smoke or hissing | Always; see lithium battery swelling |
| Smell only when a heavy load runs | Overloaded circuit, plug or socket | Note which appliance; switch it off at its own switch if safe | Smell repeats with that load |
| Smell with a buzzing or crackling sound | Arcing or a loose connection | Note where the sound comes from; do not go closer | Always |
| Smell after a storm or surge | Damaged surge protector or component | Note alarms and which breakers tripped | Always |
Safe owner checks
Only do these if there is no smoke and you are not standing near the hot area.
- Note where the smell is strongest. Inverter room, DB, battery, roof, or a particular appliance. Do not put your face close to vents or terminals.
- Photograph the inverter screen and any alarm. Many inverters log over-temperature, fan or insulation alarms that help an engineer.
- Check the app. Look at inverter temperature if shown, the load at the time, battery status and string data. Our inverter overheating guide explains temperature alarms and derating.
- Look, without touching, for brown or black marks on breakers, cables, sockets or connectors, melted plastic, or a swollen battery case. Photograph from a distance.
- Write down the pattern. Time of day, weather, which loads were running, whether a breaker tripped, and any noise. Our guide to inverter noise and humming helps describe sounds.
- Keep the system off until an engineer has checked it, even if the smell fades. A connection that overheated once will do it again.
- Send everything to your installer: photos, alarm text, app screenshots, the inverter and battery models, and your notes.
Never feel the inverter, battery or cables with your hand to "find the hot one", and never spray water or air freshener near electrical equipment.
What an engineer will check
A qualified engineer will make the system safe, then work through:
- Thermal imaging of the inverter, DB, battery terminals and roof joints under load, to find the hot spot quickly.
- Terminal tightness on breakers, busbars, inverter AC and battery terminals, and cable lugs, tightened to the specified torque.
- Cable sizing against the actual current and length; undersized cable is replaced. See our solar cable size guide.
- Breaker and isolator ratings, including whether a DC-rated device is used on the DC side. See breakers and protection.
- Inverter internals, such as fans, filters and boards, under the manufacturer's procedure and warranty rules.
- Battery condition, cell temperatures and BMS records, with the battery isolated if there is any sign of damage.
- Surge protection and earthing after storms; see our earthing and surge protection guide.
A damaged battery or inverter should not be restarted, even if it appears to work, until the engineer and, where needed, the manufacturer clear it. When it is safe to bring the system back, follow the correct sequence in our guide to restarting a solar system safely.
How to prevent overheating and burning smells
- Use correctly sized cable and DC-rated protection from the start, in a tidy DB that is not packed full.
- Ask for terminals to be re-checked during annual maintenance; connections loosen with daily heating and cooling.
- Keep the inverter shaded and ventilated, with clear vents and the clearances in its manual. See where to install the inverter and battery.
- Do not overload the backup output. Large ACs, motors and heaters may need their own planning.
- Act on early signs: discoloured breakers, a breaker that trips repeatedly (see solar breaker tripping), or a warm smell that comes and goes.
- Fit a smoke alarm near the inverter and battery area, and keep the area free of stored items.
Our fire safety guide explains the main fire risks and what a safe system includes.
How Solar Works handles it
On systems we install, our own teams size cables and protection in-house, use CHINT and TOMZN protection devices, and complete the tests for safe commissioning before handover, including showing you where your isolators are. If you are a Solar Works customer, switch off safely, then WhatsApp 0336 666 4321 with photos of the screen, the area and the inverter model. Complaints are handled by our own engineering staff; we target sending service personnel within 48 hours of a registered complaint to begin diagnosis, and repair time depends on the fault and parts. Our 1-year service warranty applies under the applicable project terms; see how after-sales service works.
We can also inspect burning-smell and overheating complaints on systems installed by other companies, as a chargeable service.
Frequently asked questions
Why is there a burning smell from my inverter?
Something is overheating: a loose terminal, an overloaded part, a failing fan or internal component, or wiring close to the inverter. Switch off in your manual's order if it is safe, keep away, and have an engineer find the source before using the system again.
Smoke from solar inverter: what should I do?
Get everyone out, close the door behind you and call Rescue 1122, telling them there is a solar system and battery. Do not use water and do not go back in. Only switch off if the switches are well away from the smoke.
Is it normal for a new inverter to smell?
Do not assume so. Any burning or hot plastic smell should be reported to your installer with photos, even on a new system. It is far better to have a connection checked than to find out later it was overheating.
What does a solar wire burning smell mean?
A cable or joint is running hot, usually because of a loose connection, a poor MC4 crimp, or cable too thin for the current. Do not touch the cable; the DC side stays live in daylight. An engineer will find it with a thermal camera and replace the damaged section.
My battery smells strange. What should I do?
A sweet, chemical or solvent smell can mean a battery is overheating or venting. Keep away, do not touch it, and call Rescue 1122 if there is smoke or hissing. Otherwise switch off only if safe and call your installer. A damaged battery should not be restarted.
Can I keep using the system if the smell goes away?
No. A connection that overheated once usually does it again, often worse. Keep the system off until an engineer has checked it.
Do you check systems installed by other companies for burning smells?
Yes, as a chargeable inspection across Punjab. Switch off safely and send photos and the inverter model on WhatsApp 0336 666 4321 first.
Sources
- Metropolitan Fire Service (South Australia), fact sheet on photovoltaic arrays and battery energy storage systems
- GivEnergy support, "What to do if you suspect a serious malfunction" (manufacturer advice on smoke and burning smells)
What you can check yourself
- From a safe location, record when the sound or smell was first noticed.
- Note which equipment was operating before the incident.
- Identify recent work from invoices or service records.
- Share an existing photograph showing the board’s location and label.
- If there are no active danger signs and a photograph can be taken without approaching the equipment, it may help. A close-up is not required. Do not touch the enclosure to judge its temperature.
What not to do
- Do not remove covers, tighten terminals, spray lubricant, cool the board with water or continue operating it to demonstrate the noise. Do not dismiss scorching because a breaker has not tripped.
When to call us
- Seek urgent electrical assistance for a burning smell, discolouration or crackling. Active smoke or fire takes priority over a service request. An ordinary persistent hum without other warning signs can still be referred for assessment, especially if it has changed.
Urgent board faults in Faisalabad and Lahore
If this is happening at a Faisalabad or Lahore property, step away first. Then call our team from a safe place with your area and what changed.
Send us
From a safe place, tell Solar Works Pakistan your city and area, the board location, symptoms, timing and recent work. Provide existing photos or equipment records if available.
Technical references
Reviewed 25 September 2026. Manufacturer documents are cited for general principles; your exact model’s manual always applies.