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I’m getting a new dishwasher with the intention of directly replacing my existing one from 15+ years ago. However I’m seeing conflicting descriptions of what is up to code, so I’m hoping someone can help.

My current dishwasher is hardwired and has no power shutoff anywhere near. I’m not home so can not check whether it is a dedicated line or 15A or 20A, or whether it has GFCI. The drain line has a high loop, not air gap, before draining to a disposal. However the Home Center I bought the appliance from says it must be a plug connection, must be GFCI, must be air gapped, and of course wants to sell me more in installation than the dishwasher costs. Looking around here and other sites I see the opposite, as well as plenty saying it is my choice.

So, in Massachusetts, is it up to code:

  • if it’s not a dedicated circuit, am I required to upgrade?

  • if it’s not 20A circuit, am I required to upgrade?

  • to direct wire, or does it need to be plugged in?

  • if direct wired, does it need a visible shut off?

  • to GFCI or not?

  • use the existing high loop, or does it need an air gap?

I’ll do whatever I need to but obviously am hoping to just install the same way the current one is. Can you help clarify the requirements?

  • Manassehkatz this should be an answer although other than commercial dishwashers all the ones I have seen are 15 amp plugs the only requirement for 20 amp circuits in the kitchen is 2 dedicated ones serving the counter tops. Even when installing a new range you do not have to update the old 3 wire 240 to 4 wire. – Ed Beal Oct 3 '18 at 18:38
  • Updating the circuit or extending it to install an accessible outlet is a bit more work if I don’t need to – D P Oct 3 '18 at 19:18
  • Welcome to DIY. If you have not done so already, take the tour: diy.stackexchange.com/tour – manassehkatz-Reinstate Monica Oct 7 '18 at 0:17
  • Must have a 20 amp rec., dedicated circuit, no direct wiring, GFCI rec. or Breaker in panel. – Top Cat May 20 at 12:44
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In general you do not have to upgrade when replacing an installed appliance, but I cannot speak for your state or municipality. In my state there is no need for even a permit as long as it is a replacement or repair. Unless there is a code violation or you simply want to upgrade for a more safe installation.

When I say code violation that would be the effective code that was in place during its installation. The famous "Grandfather clause".

Good luck

  • Grandfather clauses are always nice: everything looks up to code from when my current one was installed - thanks – D P Oct 4 '18 at 2:09
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I can't speak to Massachusetts code, so these are general comments but which should apply in most parts of the USA:

  1. Dedicated circuit - I would recommend that, even if not code required
  2. 15A vs. 20A should be determined by the dishwasher specifications. But most likely 15A is enough. I did a quick check and some current Whirlpool models only use 10A.
  3. I would always recommend direct wire for a built-in dishwasher
  4. GFCI depends on code, but if required (or not required but desired) use a GFCI breaker as that will be more convenient than buried in a cabinet behind the dishwasher.
  5. High loop installed correctly is much better, in my opinion, than a traditional air gap, but some areas don't allow it so you need to check local code. I did a quick search and couldn't find a clear answer for Massachusetts. If nobody answers here then you may want to ask a local plumber.

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