Recently a client came to us with a product emergency because they needed our help as experts at protecting critical equipment.

Their consumer power strips were starting fires in people’s homes. A significant risk that had to be fixed quickly!

Power strip - shielding prevented a retrofit To make matters worse, they had a lot of inventory: 350,000 strips.  They were planning a major retrofit that would involve disassembly, reinstallation of new components, and full retesting because the new components might have different performance characteristics which could require other components to be upgraded.

They wanted to see if we had a solution that did not involve the big – and expensive – retrofit.

The Cause

When the electricity goes through a power strip, it is conditioned or smoothed to deliver a safe voltage by a component known as a metal oxide varistor (MOV) which helps to prevent surges from reaching your household electronics by diverting the surges to ground. The client had identified that surges were causing the problem.

Unfortunately, surges are common and frequently happen – every day. Many are created internally and happen when motors start or shut off.  Refrigerators and air conditioners are the biggest culprits, but hairdryers and power tools can do it too. External surges are less frequent but can be caused by tree limbs on power lines, lightning strikes, and can even come through your telephone or cable TV lines.

MOVs degrade fractionally with each surge and with frequent surges, they were getting to a point where they started to melt with the excess heat and cause fires.

Watch what happens to an overstressed MOV when a not-uncommon surge of 6000V is applied.


The Solution

Heat resistant sleeving

DTi’s creative custom solution was to use its high-temperature fiberglass sleeving called Protect-Fast Expander to create a “sock.”  A short length was cut, stitch sealed at one end, and then placed over the MOV. This was held in place with a small dab of adhesive.  Simple, easy, effective.  It worked perfectly in client testing.

No disassembly, no replacement parts, no retesting.  Major savings.  Problem solved!




Client Benefits

  • A fast, simple, and very cost-effective solution
  • Operationally the sock installation could be done anywhere – even tabletop workstations
  • No power strips had to be returned to the factory – avoiding a significant operational/efficiency impact.
  • It was fast: we developed prototypes in a matter of weeks.
  • Flame testing confirmed that even if the MOV caught fire, it was contained within the sock.

The product that saved the day is Protect-Fast Expander.

We specialize in protecting your vital equipment with wire protection grommet edging, seals, cable management solutions and shielding/sleeving.

You can contact us to learn more or order some free samples.