I’m installing seismic straps on an electric water heater (48US gallon), and trying to follow the instructions.

there are two general instructions:

1 - place each of the two straps in bottom and upper third of the tank. this one seems self explanatory… so that the straps hold it in place.

2 - the lower strap must be at least 4" above the water heater’s controls. this one seems awfully specific, and makes more assumptions about heater construction

i’m not sure i can apply these rules to the letter, because they conflict on my particular water heater, but i might be able to do something about it if i understand reasoning behind rule 2.

The tank is probably softer and more fragile around the controls, but why "above" in particular?

Instructions: instructions

And my particular water tank, with the middle of each piece of tape marking each 1/3 mark:

water tank

(the entire bottom 1/3 is covered with an access hatch)

  • Just above the hatch is fine. Jan 24, 2023 at 10:54
  • The illustration is of a gas-fired tank. You appear to have an electric tank. I would guess that the strap being kept away from GAS controls would be to prevent the strap damaging those controls and potentially causing a gas leak. Also, below the gas controls there is shell, but no tank inside the shell. Electrics have tank all the way down to the thickness of the bottom insulation inside the shell.
    – Ecnerwal
    Jan 24, 2023 at 23:32

1 Answer 1


So that the lower strap is not too close to any opening in the tank for the controls.

The instructions are based on testing/experience with the location of sensors and their bosses to avoid breaking or damaging the sensors or tank.

  • Also, the opening in the tank wall creates a weak spot in the tank wall where shaking could cause the strap to crush the tank, potentially leading to significant additional damage. Seems like a tank that was not designed with seismic rules in mind...
    – FreeMan
    Jan 24, 2023 at 12:38
  • i understand needing to worry about proximity to weak/soft spots that could be crushed, but why specifically does it request that it be strapped above the controls? is it that if the tank slips and falls off a platform it wont rip off protrusions?
    – init_js
    Jan 25, 2023 at 19:29

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