DIY projects can be incredibly rewarding, but they also come with their own set of risks.
Accidentally hitting live electrical wires isn’t just a DIYer’s blunder; it can have immediate and dangerous consequences.
Let’s delve into the aftermath and understand how to handle this situation.
Contents (Jump to Topic)
So What Happens If You Drill Into A Live Wire?
The moment metal meets a live wire, expect an electrical spark. Depending on the wire and drill’s condition, you might also hear a loud pop.
The instant consequence typically results in a short to your electrical circuit, which normally means a power outage in the affected part of your home via the trip switch box (if not the master trip switch).
Whilst drilling through plasterboard is the most common way people accidentally hit electric wires, it can also happen when drilling through old brick and concrete.
This is exactly why all UK homes are required to have a system of trip switches, these cut the power when there’s a short circuit such as this to prevent fires.
Will I get electrocuted if I drill accidentally into a live wire?
Normally no, especially with modern drills. Unless you have a metal chuck and your hand was touching it at the time of hitting the wire, you should be protected from being electrocuted.
However, there’s always a risk of personal injury which is why it’s so important to check for wires first. Even a brief electric shock can cause injury or be fatal in severe cases.
Potential Damage To Your Drill Or Drill Bits
Your drill, being the primary point of contact, may not escape unscathed either.
The sudden surge of electricity can fry its motor or, in the worst case, cause it to catch fire. The drill bit, having directly made contact, might melt or even warp slightly.
If you smell smoke or burning plastic, switch off the drill immediately and remove the power cable or take the Lithium Ion battery out just in case.
Most modern drills (especially larger SDS drills) have some protection against accidentally drilling through an electrical cable, but there are no guarantees.
Fire Hazards
Hitting live electrical wires with a drill bit can do more than just momentarily interrupt a project. The spark can ignite any flammable material in the wall, like insulation.
Even if a fire doesn’t start immediately, damaged electrical wiring shielding can still pose a huge fire risk if left unrepaired. It’s vital to get any exposed wires repaired before you continue the job.
How To Repair Damaged Electrical Cable In A Wall
Repairing a damaged cable isn’t too difficult depending on whether the wall is plastered or tiled, but if you are not qualified it’s highly recommended you get a professional in to do the work.
Not only can you invalidate your home insurance, but you’ll be much more confident in their fix, and they will know exactly what to do and do it much faster.
1. Shutting Off The Circuit
First and foremost, turn off the power to the affected area (trip every switch including the master to be sure you’ve covered the correct circuit).
The circuit breaker in your home should be labeled for different sections but often is not depending on age.
Ensure you’ve shut off the correct one before approaching the drilled area (this is why I recommend turning off them all, as it’s not uncommon for wires to be connected to the wrong circuit).
2. Repairing The Damaged Wires
This isn’t the time for a DIY fix unless you’re trained.
Calling a qualified electrician is the safest choice. They’ll assess the damage, fix the damaged electrical wires, and ensure everything is up to code.
Prices vary up and down the UK, but assuming it’s not a big job, expect the cost to range between £60-£100.
When drilling through tiles just bear in mind that if you hit an electric wire, you will need to replace the tile as well, which can be tough if you don’t have any spares.
If you feel comfortable and have electrical experience, remember to turn off the power, gain easy access to the wire by removing a section of the wall, strip back the damaged wire, and use the correct size wire connectors or junction box to make the repair.
Typically what’s known as an ‘electrical chocolate block’ or ‘terminal block’ is used to repair broken wires. You can order these online with somewhere like Amazon, or buy them locally in a DIY store.
If you want to do a proper job, then a small junction box is your safest bet.
Once the chocolate blocks or junction box is in line with the power wire or neutral wire, it then needs to be surrounded with electrical tape. Again, this can be found online or just bought locally from a DIY/hardware store.
Prevention: How To Avoid Drilling Into Wires In The Wall
Forewarned is forearmed.
Before drilling, use should ALWAYS use a stud finder with electrical detection capabilities, commonly known as wire-tracing mode. These can often help you find water pipes and gas pipes as well.
This tool can help identify where live wires are located behind walls. Whenever possible, review blueprints or wire layouts of your home to prevent future damage.
As a rule of thumb, be wary when drilling near sockets, light switches, or places where you know wires might be running.
Typically, if done to the legal UK wiring standards, all wires should run vertically from floor to ceiling or horizontally. Rarely will you see diagonal wires. The first thing to do is test above, below, and to the left and right of the nearest switch or socket to find where your cables are running.
Vertical wiring is normally what you will find.
Then check in the area you will be drilling.
Final Thoughts & Overview
In the world of DIY, knowledge and caution are your best friends.
Understanding the consequences of drilling into a live wire and the steps to mitigate its effects can ensure your safety and save costly repairs.
Always prioritize safety over speed, and remember: when in doubt, seek professional advice.
Safety Tip: Always turn off the power when doing any work that risks electrical contact. An extra minute of precaution can save a lot of trouble.
Safe drilling!
Frequently Asked Questions
To finish off this article, here I answer some common questions that people ask when it comes to drilling into live electric wires.
What happens if you nail into a live wire?
If you accidentally nail into a live wire, you should always repair it straight away, even if your electrical system still works okay. By piecing through the metal shielding, you may have pushed live wires through into the shielding of the neutral wire, or vis versa.
Both situations are extremely dangerous.
What happens if you hit a live wire with a screw?
Hitting a live wire with a screw will likely short out your circuit and trip your trip switches. If you do accidentally hit live wires with a screw, you need to fix it properly immediately to prevent a potential fire hazard.
Do electric cables run up or down?
Generally, electrical cables run from ground level upwards, through the light switch, and up to the ceiling. For multiple sockets, you will likely find the wiring runs horizontally, through each stud post.
