Spark Electrodes: Why the Ceramic Cracks and How to Pick the Right One
What does a spark electrode do?
Two things at once, and both matter.
- It carries the high-voltage pulse from the igniter to the burner.
- It holds that voltage at a precise gap so the spark jumps exactly where the gas is.
The metal pin does the carrying. The ceramic body does the insulating — it stops the pulse leaking to earth before it reaches the tip. That ceramic is the part that fails.
Why does the ceramic crack, and why does that stop the spark?
High voltage always takes the easiest path to earth. Normally the easiest path is across the small air gap at the tip — so you get a spark where you want it.
Crack the ceramic and you offer it an easier path. The pulse now leaks straight through the crack to the metal body of the appliance. The spark still happens — just not at the burner. Sometimes you can see it arcing to the frame.
Ceramics crack from:
- Thermal shock — repeated heat cycling, then a cold clean-down.
- Mechanical knocks — during cleaning, or over-tightening on fitting.
- Age — they are consumable in a busy kitchen.
A cracked ceramic cannot be repaired or taped up. Replace it.
How do I know it's the electrode and not the igniter or lead?
- No click from the igniter → the piezo igniter has failed. Not the electrode.
- Click, but no spark anywhere → check the lead first, then the electrode.
- Click, and you can see the spark arcing to the frame or along the body → cracked electrode ceramic. This is the giveaway.
- Weak, intermittent spark → hairline crack, dirty tip, or a bad earth.
- Good spark at the right place, gas won't light → not electrical. Look at the jet.
Inspect the ceramic in good light. Hairline cracks are easy to miss and are usually near the base, where the heat is worst.
What about flame sensor electrodes — are they the same thing?
No, and it is an important distinction.
- A spark electrode creates the spark that lights the gas.
- A flame sensor electrode detects that a flame is present, and tells the control board it is safe to keep gas flowing.
Some appliances use one electrode for both jobs; many use two. If your burner lights and then shuts down a second or two later, that is a flame sensing fault, not a spark fault — the appliance lit the gas but couldn't confirm the flame.
We stock the Henny Penny pilot flame sensor electrode at £15.00 for that exact scenario.
Which electrode do I need?
Match four things:
| What to check | What we stock |
|---|---|
| Thread | M4x1 male is common on SIT assemblies |
| Length | 26.5mm, 35mm, 60mm, 67mm — it must reach the flame path |
| Straight or bent | Both — the tip has to sit in the gas stream |
| Connection | Faston, 2.8mm spade, 4.3mm tab terminal |
Our range:
- SIT Spark Electrode Straight M4x1 Male Faston 35mm — £9.99
- SIT Spark Electrode Straight M4x1 Male Faston 67mm — £7.99
- SIT Spark Electrode Bent M4x1 Male Faston 26.5mm — £7.99
- Spark Ignition Electrode 60mm Ceramic, 4.3mm Tab Terminal — £11.99
- Gas Pilot Spark Ignition Electrode Ceramic, 2.8mm Spade — £12.99
- Universal Ignition Electrode Assembly with mounting nuts — £15.00
- Henny Penny Pilot Flame Sensor Electrode — £15.00
If you can't identify yours, the universal assembly covers most commercial gas fryers and comes with mounting nuts.
How do I fit an electrode?
- Isolate the gas, let it cool.
- Pull the HT lead off the electrode terminal.
- Unscrew or unclip the electrode from its bracket — note the tip position before it moves.
- Fit the new one at the same gap and angle. The tip must sit in the gas stream, close enough to jump but not touching.
- Tighten gently. Over-tightening cracks the new ceramic — the single most common way people destroy a brand-new electrode.
- Push the HT lead fully home.
- Restore gas and test the spark before closing up.
UK commercial catering gas work must be done by a Gas Safe registered engineer qualified for commercial catering.
Frequently asked questions
Can I glue or tape a cracked ceramic?
No. Nothing you can wrap around it will stop tens of thousands of volts finding the crack. Replace it — from £5.99.
My new electrode still doesn't spark. Why?
Two usual reasons. Either it was over-tightened on fitting and the ceramic cracked immediately, or the gap and angle are wrong so the spark has nowhere useful to jump. Check both. Also confirm the earth path is clean.
How close should the electrode sit to the burner?
Close enough for the spark to jump reliably, in the gas stream, but not touching metal. The best guide is the position of the old one — which is why you note it before removing it.
How fast can I get one?
UK stock from £5.99. Order before 10am for next-day delivery, free over £25. Call 073 8051 5838 with a photo and we will identify it.
Need it identified?
Shop electrodes · Shop ignition leads · Shop piezo igniters · All gas equipment parts
Shop the parts in this guide
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Electrode
8 parts in stock
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Ignition
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Universal Ignition Electrode Assembly with Mounting Nuts for Commercial Gas Fryers
£15.00
Pilot Flame Sensor Electrode for Henny Penny Commercial Kitchen Equipment
£15.00
Gas Pilot Spark Ignition Electrode Ceramic 2.8mm Spade for Commercial Gas Appliances
£12.99
Spark Ignition Electrode 60mm Ceramic 4.3mm Tab Terminal for Commercial Gas Oven
£11.99
