HHO Safety Equipment Defined

Safety equipment not only saves you from getting hurt, it also protects your HHO system and more importantly, your car!!  HHO gas can be very dangerous. Not only is it flammable, but explosive, even in small quantities.

Auto-Hydrogen-USA WILL NOT BE HELD RESPONSIBLE for any damage or harm caused by HHO Systems

Do your own research first and learn about the product your using

Below are a few safety devices:

hho bubbler tank with bracket


This is a simple yet very important part of any HHO system.

The bubbler has 2 benefits;

  1. it protects your generator from a flashback (caused by backfire)
  2. it acts as a filter to clean the bubbles that are made by your generator, from unwanted particulates that may be present, depending on your chosen electrolyte and other factors.

The bubbler is simply a container half filled with water. HHO gas is fed to the bottom of the bubbler with a hose from your electrolyte tank and allowed to bubble through the water. The HHO gas continues through a hose from the top of the bubbler "filtered" to the engine.

Some bubblers are designed to allow the top to pop off in the event of a backfire.

This method is 100% effective as a safety feature. (View Product)

The photos below show the effects of electrolyte (carried by steam) on aluminium engine parts.

MAF HHO Electrolyte Damage

MAF Electrolyte Damage

  • These parts came from a car "without" a bubbler.
  • If there was a bubbler before the intake this would not have happened

Flash Arrestor


This is another simple yet invaluable device designed to snuff out any flashback (backfire) from the engine. A majority of these devices are constructed of a tube gently packed with fine bronze wool and fitted with hose barbs on each end. Bronze wool is used because of its resistance to oxidation (rust).

These devices are not 100% effective so use with a bubbler with pop of lid.

Piston Popper Flashback Arrestor / Flashport Device

piston popper flashback arrestor dismantled


 HOW IT WORKSThis HHO Safety Valve Flashback Arrestor is installed on your HHO Bubbler and will relieve any pressure in case of Flashback from your vehicles air intake.

When a flashback occurs, the flame from your air intake will travel back to your HHO Bubbler in a split second and ignite the HHO gas above the water level in the top portion of your bubbler tank.

Few bubblers are strong enough to withstand the explosive pressure of the HHO gas.

If the "HHO Auto Reload Piston Popper" is installed to your bubbler tank, THE SPRING LOADED PISTON WILL RISE to let the explosive gas escape through the EXHAUST PORTS/VENTS alleviating the pressure instantly.

Then the piston is forced back downward by the stainless steel spring Automatically resealing itself.

Simple yet the most effective way of controlling flashback! (View Product)

Check Valve

Another inexpensive safety device used is a check valve or one-way valve which allows gas to flow thru only in one direction. DO NOT rely solely on a check valve to protect your HHO system from a flashback/backfire.








These devices are not 100% effective so use with a bubbler with pop off lid.


Simply put, all HHO systems great and small are subject to electrical shorts.

30 amp HHO circuit breaker

fuse-30 amp HHO

Medium to large HHO systems can pull anywhere from 15 to 40 amps (depending on the design) so a short can cause serious damage under the hood unless a simple, inexpensive fuse shuts things down before it gets out of hand.

The fuse should be installed as close to car battery as possible, on the positive power feed to your relay or PWM and should be properly sized.

auto hydrogen 60 amp HHO specific PWM and in car digital display

PWM - (Pulse Width/Wave Modulators)


These handy devices are a must for any generator that could overheat. These units act like a limiter by allowing you to limit the amount of amps your generator can pull. The last thing you want is a HHO generator getting too hot as you are not only very inefficient but risk damaging your HHO generator. Another issue with a hot HHO generator is the water will boil and water vapors will enter your engine causing serious and costly damage. Professionally built HHO systems which have been thoroughly tested may not need a PWM. (View Product)

 AMP Gauge

hho amp gauge digitalHHO-amp-gauge-analog

It is very handy to install a Amp Gauge under the hood to allow for a quick read on your systems performance by glancing under the hood.

Proper Wiring

HHO copper-wire-cable-red-and-black

Wire is cheap; don't let a poor wiring design limit the performance of your HHO system. There are a number of simple wiring diagrams that are easy to follow that are safe. Good, quality connectors are also very important as poor connections will overheat and could short.

Attention Do-It-Yourselfers

Anyone who is mechanically inclined can build and install an HHO system.

By system we mean HHO generator, bubbler, safety device and likely a sensor adjuster or two. Undoubtedly, the #1 suggestion is do your homework before you start your project.

Do NOT pay for an e-book as the information is FREE.

Some questions you should ask yourself:

  1. How much output do I need?
  2. What kind of space do I have under my hood?
  3. What style generator do I want to make? For example, generator housing, internal components made of wire, plates, mesh, etc.
  4. Where can I find all of the parts? It's never fun to be half-way into a project to hit a snag by not finding all of the parts.
  5. Did I think of everything? Generator, bubbler, flash arrestor, automotive wire (Not the same as building wire), etc.scratching head
  6. What will this cost me? You may find the cost of your unit might exceed a professionally pre-built system and may not be as good as a professionally built unit. We're not trying to talk you out of it but want you to know what you're getting into ahead of time.

Other notes to consider:

  1. HHO gas is very dangerous. It's not only flammable but explosive even in small quantities. Auto-hydrogen WILL NOT BE HELD RESPONSIBLE for any damage or harm caused by HHO systems. You can never be too safe; you should have at least 2 safety mechanisms in your HHO system.
  2. The engine compartment is not a friendly environment. Most home-made generators tend to get very hot so take care in finding housings capable of withstanding excess heat.
  3. NEVER use a glass generator in your engine. If the HHO gas ignites the glass fragments could seriously hurt you.
  4. The electrolysis process will degrade most metals fairly quickly, be sure to use only stainless steel of the highest quality you can afford which includes all hardware.
  5. Once you decide on your design, try to find someone who's made it before and ask questions. We have yet to find someone unwilling to discuss their HHO project and offer pointers.
  6. Once you're system is constructed, test it and monitor it carefully BEFORE installing it in your ride. Check for overheating wires or wire connections as well as possible leaks.
  7. There are a number of very helpful HHO forums, read as much as possible.