Troubleshooting Colour Smart Bulbs: 10 Common Problems Fixed

Your new colour smart bulbs arrived. You installed them with excitement. And then… something went wrong. They won’t connect. The colours look wrong. They keep dropping offline. Before you box them up for return, read this guide.

Smart bulbs are remarkably reliable—when they work. But like any technology, they can misbehave. The good news? Most problems have simple fixes.

In our years of testing smart bulbs across dozens of UK homes, we’ve encountered every issue imaginable. We’ve fixed them all. And now we’re sharing those solutions with you.

This guide covers the 10 most common problems with colour smart bulbs:

1. Bulb won’t connect – The bulb is installed but your app can’t find it
2. Colours don’t match expectations – That purple looks more like pink
3. Bulb keeps disconnecting – It works, then drops off, then works again
4. Voice control not working – Alexa/Google/Siri ignores your commands
5. Flickering or buzzing – The bulb makes noise or light fluctuates
6. Bulb gets hot – Is that normal or a fire risk?
7. App not finding bulb – The app searches but finds nothing
8. Automations not running – Your sunset routine doesn’t trigger
9. Bulb won’t dim – Stuck at full brightness
10. One bulb in group not responding – All others work except this one

For each problem, we’ll explain:

• Why it happens (so you understand the cause)
• How to fix it (step-by-step instructions)
• When to give up (and call an electrician or return the bulb)

Plus UK-specific advice on wiring, fittings, and safety.

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Before You Start – Universal Quick Fixes

Some fixes work for multiple problems. Try these first:

The 5-Second Reset

1. Turn bulb off at wall switch
2. Wait 5 seconds
3. Turn on
4. Check if problem resolved

The Full Power Cycle

1. Turn bulb off at wall switch
2. Wait 30 seconds
3. Turn on
4. This allows capacitors to discharge fully

The App Refresh

1. Close app completely
2. Reopen
3. Wait 30 seconds for status to update

The Network Refresh

1. Restart your router
2. Restart your hub/Bridge (if applicable)
3. Wait 5 minutes for everything to reconnect

The Factory Reset

Most smart bulbs reset when turned off and on 5 times:

1. Off-on-off-on-off-on-off-on-off-on (5 cycles)
2. Bulb should flash or pulse to confirm reset
3. Re-add to app as new bulb

See our review of some of the best Philips Essential smart bulbs

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Problem 1 – Bulb Won’t Connect

Symptoms

• App searches but doesn’t find the bulb
• Bulb doesn’t appear in device list
• Setup process fails repeatedly

Possible Causes

Cause	Likelihood	Affected Brands
Bulb not in pairing mode	High	All
Phone on 5GHz Wi-Fi (bulb needs 2.4GHz)	High	Wi-Fi bulbs (Amazon, TP-Link, Govee)
Bluetooth range too far	Medium	Bluetooth bulbs (Hue without Bridge)
Bulb already connected to another account	Medium	All
Faulty bulb	Low	All

Solutions

Solution 1: Put Bulb in Pairing Mode

1. Turn bulb off at wall switch
2. Turn on for 2 seconds, off for 2 seconds
3. Repeat 5 times
4. On the 5th on, bulb should flash or pulse
5. Try connecting again

UK Note: Some UK light switches are slow to respond. Ensure you’re pausing long enough (count “one-thousand-and-one, one-thousand-and-two”).

Solution 2: Check Wi-Fi Frequency (Wi-Fi Bulbs)

Many smart bulbs only work on 2.4GHz Wi-Fi, not 5GHz. This is because 2.4GHz offers better range and penetration through walls than 5GHz.

How to fix:

1. Go to phone Wi-Fi settings
2. Check which network you’re connected to
3. If it’s a 5GHz network, switch to 2.4GHz
4. Some routers broadcast both with same name – you may need to:
   • Temporarily disable 5GHz in router settings
   • Move closer to router (phone may switch to 2.4GHz)
   • Use router app to separate bands

UK-specific: Virgin Media, Sky, BT routers often have combined bands. Check your router’s manual for how to separate them.

Solution 3: Move Closer (Bluetooth Bulbs)

Bluetooth range is approximately 10 metres in open air, less through walls.

How to fix:

1. Move phone within 1-2 metres of bulb
2. Ensure no large metal objects between phone and bulb
3. Try again

Solution 4: Check if Bulb Is Already Connected

Some bulbs come pre-paired or may have been returned and not reset.

How to fix:

1. Try the 5-cycle reset (Solution 1)
2. If that doesn’t work, the bulb may be linked to another account
3. Contact manufacturer support with proof of purchase

Solution 5: Check Hub Connection (Hub-Based Systems)

For Hue, IKEA, etc., ensure hub is working.

Philips Hue specifically:

1. Check Bridge lights (3 green = good)
2. Ensure Bridge is connected to router via Ethernet
3. Restart Bridge (unplug, wait 30 seconds, plug in)
4. Press button on Bridge when app prompts

Solution 6: Try Another Phone

Some phones have Bluetooth or Wi-Fi compatibility issues.

How to fix:

1. Borrow another phone (different brand if possible)
2. Download the same app
3. Try setup again
4. If it works, your original phone may have issues

When to Give Up

If you’ve tried all solutions and the bulb still won’t connect after 30 minutes, it may be faulty. Return it.

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Problem 2 – Colours Don’t Match Expectations

Symptoms

• Purple looks pink, red looks orange
• Whites look blue or yellow
• Colours less vibrant than expected
• Different bulbs show different colours

Possible Causes

Cause	Likelihood	Affected Brands
Bulb has limited colour range (16 presets vs 16M)	High	Amazon Basics, budget brands
App settings incorrect	Medium	All
Bulb quality variation	Medium	Budget brands
Colour temperature confusion	Medium	All
Calibration issues	Low	Some

Solutions

Solution 1: Understand Your Bulb’s Capabilities

Not all “colour” bulbs are equal:

Bulb Type	Colour Capability	Typical Brands
16 million colours	Full RGB spectrum	Philips Hue, Nanoleaf, TP-Link, Govee
16 presets	Fixed colour options	Amazon Basics, some budget bulbs
RGBIC	Multiple colours simultaneously	Govee (strips), some specialty bulbs

If you have a 16-preset bulb: You can’t get every colour. Accept the limitations or upgrade.

Solution 2: Check Colour Temperature Settings

Some apps have separate controls for:

• Colour (RGB)
• White temperature (warm to cool)

Ensure you’re in colour mode, not white mode.

Solution 3: Calibrate (If Available)

Some apps have calibration options:

Philips Hue:

1. Go to Settings → Light setup
2. Select bulb
3. Look for calibration options (not all bulbs have this)

Nanoleaf:

1. Go to Device Settings
2. Look for colour calibration (limited)

Solution 4: Check for Firmware Updates

Manufacturers sometimes improve colour accuracy with updates.

How to check:

1. Open app
2. Look for “Firmware update” or “Check for updates”
3. Update if available

Solution 5: Compare with Another Bulb

If you have multiple bulbs:

1. Set both to same colour (e.g., pure red)
2. Compare side by side
3. If they differ significantly, one may be faulty

Solution 6: Understand LED Limitations

Some colours are harder for LEDs to reproduce accurately:

• Deep purple
• True red
• Yellow (can look greenish)

This is a technology limitation, not necessarily a fault.

When to Give Up

If colours are consistently wrong across multiple bulbs and apps, the brand may not meet your expectations. Consider switching to a premium brand like Philips Hue.

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Problem 3 – Bulb Keeps Disconnecting

Symptoms

• Bulb works, then stops responding
• App shows “offline” or “unavailable”
• Bulb reconnects after a while
• Happens multiple times per day/week

Possible Causes

Cause	Likelihood	Affected Brands
Weak signal (Wi-Fi/Bluetooth/Zigbee)	High	All
Too many devices on network	Medium	Wi-Fi bulbs
Interference from other electronics	Medium	All
Hub placement issue	High	Hub-based systems
Bulb acting as weak mesh node	Medium	Mesh systems

Solutions

Solution 1: Check Signal Strength

For Wi-Fi bulbs (Amazon, TP-Link, Govee):

1. Move bulb closer to router temporarily
2. If it stabilises, signal strength is the issue
3. Consider Wi-Fi extender or mesh system

For Bluetooth bulbs:

1. Move phone closer to bulb
2. If stable, range is issue – consider adding a hub

For Zigbee bulbs (Hue, IKEA):

1. Check distance to nearest bulb
2. Add more bulbs to strengthen mesh
3. Ensure hub is centrally located

Solution 2: Reduce Network Congestion

UK homes now have dozens of connected devices. Wi-Fi congestion is real.

How to fix:

1. Check how many devices on your network
2. Consider upgrading router (ISP routers are often poor)
3. Separate 2.4GHz and 5GHz bands
4. Move some devices to 5GHz, leaving 2.4GHz for bulbs

Solution 3: Identify Interference Sources

Common interference sources in UK homes:

• Microwave ovens (2.4GHz)
• Baby monitors
• Cordless phones
• Neighbour’s Wi-Fi (especially in flats/terraces)

How to fix:

1. Temporarily turn off suspected devices
2. See if bulb stabilises
3. If yes, relocate bulb or interfering device

Solution 4: Optimise Hub Placement (Hue, IKEA)

For Philips Hue:

1. Bridge should be central, not hidden in cupboard
2. Avoid placing near other electronics
3. Ensure it’s connected via Ethernet (not Wi-Fi)
4. Consider moving Bridge to first-floor landing (as per period homes guide)

Solution 5: Strengthen Zigbee Mesh

Zigbee networks get stronger with more devices, many thanks to the mesh network architecture:

1. Add at least one bulb in hallway/landing (central location)
2. Ensure bulbs are powered on (they repeat even when off? No – they need power)
3. Add a smart plug (many act as repeaters)

Solution 6: Change Zigbee Channel

Zigbee operates on the same 2.4GHz frequency as Wi-Fi. Channel conflict can cause issues.

For Hue:

1. Go to Settings → Bridge settings
2. Check Zigbee channel
3. Change to less congested channel (experiment)

Note: This is advanced. Only attempt if you understand networking.

When to Give Up

If disconnections persist after all solutions, the bulb may be faulty. However, if multiple bulbs disconnect, it’s your network, not the bulbs.

Related reading: Find out the perfect smart bulb for every type of room

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Problem 4 – Voice Control Not Working

Symptoms

• Alexa/Google/Siri says “Sorry, I can’t find that device”
• Commands are ignored
• Some commands work, others don’t
• Voice control worked before, now doesn’t

Possible Causes

Cause	Likelihood	Affected Brands
Skill/action not linked properly	High	All (with voice integration)
Account linking expired	Medium	All
Device names not recognised	High	All
Speaker out of range (Bluetooth)	Medium	Bluetooth setups
Cloud service outage	Low	All

Solutions

Solution 1: Re-link the Skill/Action

For Alexa:

1. Open Alexa app
2. Go to “Skills & Games”
3. Find your bulb’s skill (Philips Hue, Nanoleaf, etc.)
4. Select “Disable Skill”
5. Wait 10 seconds
6. Select “Enable Skill”
7. Re-link your account (follow prompts)
8. Say “Alexa, discover devices”

For Google Home:

1. Open Google Home app
2. Tap Settings → Works with Google
3. Find your bulb’s service
4. Tap “Unlink account”
5. Tap “Link account” and re-authorise
6. Say “Hey Google, sync devices”

For Apple HomeKit:

1. Open Home app
2. Find problematic bulb
3. Remove from Home (settings → remove accessory)
4. Re-add using HomeKit code

Solution 2: Check Device Names

Voice assistants need simple, recognisable names.

Bad names:

• “Living Room Bulb 1”
• “LR_01_Left_Sconce”
• “Philips Hue 3”

Good names:

• “Living Room Main”
• “Kitchen Lights”
• “Bedroom Lamp”

How to fix:

1. Rename bulbs in manufacturer’s app
2. Voice assistant should sync automatically
3. If not, force sync (see Solution 1)

Solution 3: Check Speaker Range (Bluetooth Setups)

If you’re using Bluetooth bulbs without a hub:

1. Ensure speaker is within 10 metres of bulbs
2. Reduce obstacles between speaker and bulbs
3. Consider adding a hub to move to Zigbee/Wi-Fi

Solution 4: Check Cloud Status

Sometimes the problem isn’t you:

Check:

• Philips Hue: status.meethue.com
• Amazon Alexa: amazon.co.uk/alexa-status
• Google Home: google.com/appsstatus

Solution 5: Reboot Everything

1. Reboot router
2. Reboot hub/Bridge
3. Reboot smart speaker
4. Try again

When to Give Up

If voice control works in the app but not via voice, it’s a voice integration issue. If it doesn’t work in app either, see Problem 1.

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Problem 5 – Flickering or Buzzing

Symptoms

• Light visibly flickers (may be subtle or obvious)
• Bulb makes buzzing/humming sound
• Happens at certain brightness levels
• Worse when dimmed

Possible Causes

Cause	Likelihood	Affected Brands
Incompatible wall dimmer	Very High	All (when used with traditional dimmers)
Loose connection	Medium	All
Voltage fluctuations	Low	All
Faulty bulb	Medium	All

Solutions

Solution 1: Remove Wall Dimmer (Critical)

This is the most common cause in UK homes.

Smart bulbs are designed to be used with constant power. They have their own dimming electronics. Putting them on a traditional wall dimmer causes:

• Flickering
• Buzzing
• Potential damage to bulb
• Fire risk (in extreme cases)

How to fix:

1. Replace wall dimmer with standard on/off switch
2. OR bypass dimmer (leave at 100% and use app/voice for dimming)
3. OR install smart dimmer designed for smart bulbs

UK Note: Many UK homes have dimmer switches. If you have one, this is almost certainly your problem.

Solution 2: Check Connections

Loose wiring can cause flickering:

1. Turn off power at consumer unit (fuse box)
2. Remove bulb
3. Check socket contacts are clean and not corroded
4. Reinsert bulb firmly
5. For B22: push and twist until locked
6. For E27: screw until finger-tight (not overtight)

Solution 3: Test on Another Circuit

1. Move bulb to a different light fitting (preferably one without dimmer)
2. If flickering stops, original circuit is issue
3. If flickering continues, bulb may be faulty

Solution 4: Check for Voltage Issues

UK mains voltage should be 230V ±10%. If your home has voltage fluctuations:

1. Observe if flickering coincides with other appliances (kettle, washing machine)
2. Consider having electrician check your supply
3. This is rare in modern UK homes but possible in rural areas

Solution 5: Return Faulty Bulb

If none of the above helps, the bulb may be faulty:

1. Test with another bulb in same socket
2. If other bulb works fine, return original

When to Call an Electrician

Call an electrician if:

• Flickering persists after removing dimmer
• You smell burning
• Switch feels hot
• Multiple bulbs on same circuit flicker

UK safety: Electrical issues are not DIY if you’re unsure. A qualified electrician is worth the cost.

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Problem 6 – Bulb Gets Hot

Symptoms

• Bulb feels warm/hot to touch
• Concern about fire risk
• Heat noticeable after short use

Solutions

Solution 1: Understand Normal Operating Temperature

LED bulbs get warm. This is normal.

• Standard LED bulb: 30-60°C (warm to hot)
• GU10 downlights: Can reach 60-70°C (hot)
• Enclosed fittings: Hotter (less ventilation)

What’s normal:

• You can touch briefly without burning
• Bulb cools down quickly when off
• No discolouration or melting

What’s not normal:

• Too hot to touch (above 70°C)
• Smell of burning
• Discolouration of bulb or fitting
• Melting plastic

Solution 2: Check Ventilation

LED bulbs need airflow to cool.

How to fix:

1. Ensure bulb not in completely enclosed fitting (check specifications)
2. Some bulbs are rated for enclosed fittings – check packaging
3. If in enclosed fitting and hot, consider moving to open fitting

Solution 3: Check Wattage

Smart bulbs typically use 8-10W. This is fine for standard fittings.

However: If your fitting has a maximum wattage rating (e.g., “Max 40W”), an 8W LED is fine. Older fittings may have lower ratings due to heat build-up.

Solution 4: Check for Faulty Bulb

If bulb is excessively hot:

1. Stop using immediately
2. Contact manufacturer
3. Return if under warranty

When to Worry

Worry if:

• Bulb is too hot to touch
• You smell burning
• Fitting discolours
• Bulb makes sizzling sound

Otherwise, warm is normal.

Read also: Colour smart bulbs vs. white Ambiance bulbs

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Problem 7 – App Not Finding Bulb

Symptoms

• App opens but can’t find any bulbs
• “No devices found” message
• Bulbs worked before, now app shows nothing

Possible Causes

Cause	Likelihood	Affected Brands
Bluetooth off on phone	High	Bluetooth setups
Phone not on correct Wi-Fi	High	Wi-Fi bulbs
Hub/Bridge offline	High	Hub-based systems
App permissions revoked	Medium	All
Account logged out	Medium	All

Solutions

Solution 1: Check Basic Phone Settings

For Bluetooth bulbs:

1. Ensure Bluetooth is enabled on phone
2. Ensure phone not in Airplane mode
3. Move closer to bulbs

For Wi-Fi bulbs:

1. Ensure phone connected to same Wi-Fi as bulbs
2. Check you’re on 2.4GHz if bulbs require it
3. Restart phone Wi-Fi

Solution 2: Check Hub/Bridge Status

For Philips Hue:

1. Look at Bridge lights
2. Three green lights = good
3. If lights off/orange, restart Bridge

For IKEA:

1. Check Gateway lights
2. Restart if needed

For Nanoleaf (Thread):

1. Check Thread Border Router status
2. Restart if needed

Solution 3: Check App Permissions

iOS:

1. Go to Settings → [App Name]
2. Ensure Bluetooth/Local Network permissions enabled

Android:

1. Go to Settings → Apps → [App Name] → Permissions
2. Ensure Location/Nearby devices enabled

Solution 4: Log Out and Back In

1. Log out of app
2. Close app completely
3. Reopen and log in
4. Check if bulbs reappear

Solution 5: Reset App Data

iOS:

1. Delete app
2. Reinstall from App Store
3. Log in again

Android:

1. Clear app cache (Settings → Apps → [App] → Storage → Clear cache)
2. If that fails, clear data (warning: loses settings)

When to Give Up

If app works but shows no bulbs after all steps, bulbs may need re-adding. See Problem 1.

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Problem 8 – Automations Not Running

Symptoms

• Sunset routine doesn’t trigger
• Geofencing doesn’t turn lights off when you leave
• Timers don’t work
• Some automations work, others don’t

Possible Causes

Cause	Likelihood	Affected Brands
App permissions restricted	High	iOS devices
Phone location services off	High	Geofencing issues
Time zone incorrect	Medium	All
Automation deleted/corrupted	Medium	All
Hub/Bridge offline	Medium	Hub-based systems

Solutions

Solution 1: Check App Permissions (iOS Critical)

For iOS users: Apple restricts background app activity.

How to fix:

1. Go to Settings → [App Name]
2. Ensure Location set to “Always” (not “While Using”)
3. Ensure Background App Refresh enabled
4. Ensure Notifications enabled (for some apps)

Without “Always” location, geofencing won’t work.

Solution 2: Check Location Services

For Android:

1. Go to Settings → Location
2. Ensure location is on
3. Ensure app has location permission

For both platforms:

1. Test with a simple timer automation
2. If timer works but geofencing doesn’t, location is the issue

Solution 3: Check Time Zone

1. Ensure phone time zone is correct
2. Ensure hub/Bridge time zone matches (if applicable)
3. Sunset calculations depend on correct location/time

Solution 4: Recreate Automation

Sometimes automations become corrupted:

1. Delete problematic automation
2. Create new one from scratch
3. Test immediately

Solution 5: Check Hub/Bridge Status

Automations often run from hub, not phone:

1. Ensure hub/Bridge online
2. Check hub logs (if available) for automation triggers
3. Restart hub

Solution 6: Check for Conflicting Automations

Multiple automations can conflict:

1. Review all automations
2. Check for overlapping schedules
3. Disable others temporarily to test

When to Give Up

If automations work in app but don’t trigger, it’s likely a phone permission issue. If they don’t work at all, recreate them.

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Problem 9 – Bulb Won’t Dim

Symptoms

• Bulb only at 100% brightness
• Dimming slider has no effect
• Bulb flickers when trying to dim

Possible Causes

Cause	Likelihood	Affected Brands
Wall dimmer present	Very High	All
Bulb not dimmable	Low	Very few smart bulbs (most are dimmable)
App issue	Medium	All
Firmware issue	Low	All

Solutions

Solution 1: Remove Wall Dimmer (Critical)

As with flickering, wall dimmers are the #1 cause of dimming issues.

Smart bulbs need constant power. Wall dimmers reduce power, confusing the bulb.

How to fix:

1. Replace wall dimmer with standard on/off switch
2. OR bypass dimmer (set to 100% and leave it)
3. Use app/voice for dimming

Solution 2: Check Bulb Type

Almost all smart bulbs are dimmable, but check:

• Philips Hue: All dimmable (2%-100%)
• Nanoleaf: All dimmable (1%-100%)
• Amazon Basics: Dimmable (5%-100%)
• TP-Link: Dimmable

If you somehow bought a non-dimmable smart bulb (rare), replace it.

Solution 3: Test in App

1. Open manufacturer’s app (not voice)
2. Try dimming slider
3. If works in app but not voice, see Problem 4
4. If doesn’t work in app, continue

Solution 4: Check Firmware

1. Check for firmware updates
2. Update if available
3. Test dimming again

Solution 5: Reset Bulb

1. Perform 5-cycle reset
2. Re-add to app
3. Test dimming

When to Give Up

If bulb still won’t dim after removing wall dimmer and resetting, it may be faulty. Return it.

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Problem 10 – One Bulb in Group Not Responding

Symptoms

• Group command controls most bulbs
• One bulb ignores commands
• Individual control of that bulb works
• Bulb sometimes responds, sometimes doesn’t

Possible Causes

Cause	Likelihood	Affected Brands
Weak signal to that bulb	High	Mesh systems
Bulb out of sync	Medium	All
Bulb in wrong group	Medium	All
Bulb needs reset	Medium	All

Solutions

Solution 1: Check Signal Strength

For mesh systems (Zigbee/Thread):

1. This bulb may be at edge of mesh
2. Add bulb between it and rest of network
3. Move hub closer if possible

For Wi-Fi bulbs:

1. Check distance to router
2. Consider Wi-Fi extender

Solution 2: Remove and Re-add to Group

1. Remove bulb from group in app
2. Save changes
3. Re-add bulb to group
4. Test

Solution 3: Reset and Re-add Bulb

1. Perform 5-cycle reset on problem bulb
2. Re-add to system (may auto-appear in groups)
3. Test

Solution 4: Check for Firmware Differences

If bulb has different firmware version:

1. Check firmware on all bulbs
2. Update problem bulb if behind

Solution 5: Move Bulb Temporarily

1. Move problem bulb to location of working bulb
2. If it works there, original location has signal issue
3. If it still doesn’t work, bulb may be faulty

When to Give Up

If bulb works individually but not in group, it’s a grouping issue. If it doesn’t work individually either, see Problem 1.

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When to Call an Electrician (UK Safety Advice)

Some issues require professional help. Call an electrician if:

1. You Suspect Wiring Issues

• Flickering across multiple bulbs on same circuit
• Switches feel hot
• Burning smell from fittings
• Circuit breaker trips when using lights

2. You Need to Replace Switches

• Installing smart switches that require neutral wires
• Replacing dimmers with standard switches
• Any work inside your consumer unit (fuse box)

3. You Have an Older Home

• Pre-1960s wiring may not meet modern standards
• No earth wiring in some very old fittings
• Rubber-insulated cables (dangerous)

4. You’re Unsure

• If in doubt, call a professional
• UK electrical work should comply with Building Regulations
• Some work requires notification to local authority

Finding a Qualified Electrician

In the UK, look for:

• Registered with a competent person scheme (NICEIC, ELECSA, NAPIT)
• Part P registered (for notifiable work)
• Check reviews on TrustATrader, Checkatrade, Rated People
• Get multiple quotes for larger jobs

Related Reading:

• [ Setting up colour smart bulbs for British apartments]
• [PHILIPS Essential smart bulbs setup guide]
• [The best colour smart bulbs for period homes]