How electric hob glass lids can break - beware!

When you’re staying in a motorhome, the last thing you want to worry about are your appliances breaking down - or worse, them exploding or cracking. One issue we’ve come across recently that motorhome owners should be aware of is the potential for their glass electric hob lid to break. Understanding how and why this can occur can help you prevent it from happening to your appliance, and therefore hopefully ensure that your cooking setup remains intact and safe to use.

Glass electric hob lids

The glass used on electric hob lids is typically toughened or tempered glass. This type of glass is designed to withstand high temperatures and pressure, making it a popular choice for kitchen appliances. However, despite its strength, toughened glass can still crack or shatter under certain conditions. We’ve seen an incident recently whereby the electric hob dial was left turned on, then the vehicle was plugged in to an electric hook up and the hob turned itself back on, even with the lid closed. A couple of minutes later the glass lid exploded, with bits of glass flying everywhere. It’s worth taking note of this, and being aware that a safety cut-off feature may not be in place for all makes and models of hob, so the hob may work even if the glass lid is in the lowered position.

Some of the main causes of glass lid breakages

Thermal shock

This is one of the primary reasons glass lids can crack. When the glass is exposed to sudden changes in temperature, it can expand or contract rapidly. In a motorhome, the hob lid may be closed immediately after cooking, trapping residual heat. If the hob is then subjected to cool air (like when a window or door is opened) or something very cold from the fridge, the sudden temperature change could cause the glass to crack.

Vibration and movement

Motorhomes are constantly on the move, and this motion creates vibrations. Even if they are subtle, these vibrations can exert stress on the glass over time. Continuous movement and jolting, especially on rough roads, can weaken the glass structure and eventually lead to cracks.

Impact damage 

Motorhomes are compact spaces, and sometimes, objects can fall or bump into the hob lid. Even though tempered glass is sturdy, a strong enough impact at the right (or wrong) angle can cause it to crack or shatter. It’s a good idea to not store heavy items in the cupboards and shelves above the hob, in case they fall.

Manufacturing defects

While less common, imperfections during the manufacturing process can leave the glass more susceptible to cracking. These defects might not be visible immediately, but can manifest under stress.

Improper installation 

If the electric hob lid was not installed correctly, uneven pressure points can cause stress on the glass. Over time, this stress can lead to cracks.

How to stop damage from happening

Avoid sudden temperature changes 

After cooking, allow the hob to cool down gradually and then put the lid down. Avoid creating a cold draft directly over the hob or putting the lid down with something cold on top of it.

Secure items during travel

Ensure that no heavy or sharp objects are placed above or around the hob that could fall during travel. Using non-slip mats and securing any loose items can help.

Regularly inspect the glass lid

Regularly check the condition of the glass lid and the hob’s installation. Look for any signs of stress, or minor/hairline cracks and address them before they become larger issues.

Ensure it’s properly installed if replacing

Ensure that the hob lid is installed by a professional. Proper installation can prevent uneven pressure and potential stress points on the glass.

Use hob guards

Consider using a hob guard or cover that can provide an additional layer of protection against impact and vibrations.

If it’s ever happened to you, you will no doubt remember how scary and loud it was to have the glass explode, and obviously how worrying the clean up afterwards was, where you needed to find every last shard of glass from every nook and cranny. If you can put in place the preventative measures above, you will hopefully reduce the risk of your hob lid exploding or cracking, ensuring your mobile kitchen remains both functional and safe. Happy cooking!