Author Topic: Ot: Dishwashers  (Read 14932 times)

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Offline drussell

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Re: Ot: Dishwashers
« Reply #100 on: January 24, 2021, 06:29:50 pm »
Of course it's also true that you have to consider other appliances on the same circuit, especially things you can't avoid using like the refrigerator.

The fridge receptacle is required to be on its own dedicated circuit.   ;)

I understand what you're saying though, but a 1000W dishwasher is no different than plugging in a 1500W toaster or deep fryer or something.  Most kitchens built in the past 50-60 years are going to have at least a couple circuits available for "heating" appliances, even in most of the oldest, smallest examples.

When specifically wiring for a fixed-mount dishwasher it has pretty much always been recommended best practice in north America to run a 12ga to the dishwasher, even if the originally installed model needs less and you even use a 15A breaker.  That way even the ones with beefy heating elements in them can be used later if desired, with at most a breaker change no actual rewiring required.  You could even go to a 240v unit if future requirements dictated.
 

Offline rsjsouza

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Re: Ot: Dishwashers
« Reply #101 on: January 24, 2021, 07:27:15 pm »
Of course it's also true that you have to consider other appliances on the same circuit, especially things you can't avoid using like the refrigerator.

The fridge receptacle is required to be on its own dedicated circuit.   ;)
Maybe in Canada, because in the houses that I lived here in the US... What a mess.

Quite different than Brasil, where houses above a certain area were required to completely segregate outlets from lighting circuits and built-in appliances (wall aircons, washers, boilers, shower head heaters, etc.).

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Oh, the "whys" of the datasheets... The information is there not to be an axiomatic truth, but instead each speck of data must be slowly inhaled while carefully performing a deep search inside oneself to find the true metaphysical sense...
 

Offline drussell

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Re: Ot: Dishwashers
« Reply #102 on: January 24, 2021, 10:15:15 pm »
Maybe in Canada, because in the houses that I lived here in the US... What a mess.

Huh...  you're right.  I always thought that one was the same in the US NEC as it is here...

Still obviously "best practice," but apparently still not required, even as of the 2020 NEC!

Crazy!!   :o

 

Offline Nusa

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Re: Ot: Dishwashers
« Reply #103 on: January 25, 2021, 01:04:43 am »
Even the 1950's house I'm living in now has a 20 amp circuit for the kitchen. But only one of them. Everything in the kitchen is on that single circuit, except for ceiling lights. Since I live alone now, that's manageable with a one-major-appliance-at-a-time rule, plus the refrigerator. Stove is gas, so that doesn't count.
 

Offline tom66

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Re: Ot: Dishwashers
« Reply #104 on: January 25, 2021, 10:08:01 am »
I have a similar capacity issue in my household.  The kitchen and downstairs circuit share 32A.  The tumble dryer, dishwasher and washing machine all active use about 28-29A.  I also occasionally want to charge my PHEV via a kitchen socket, and I haven't yet put in a wall box for it (didn't seem necessary this time when I moved) so that's another 10A.  So I need to balance load carefully especially overnight to avoid tripping circuits.

It seems to be now quite common in new UK homes to combine kitchen and downstairs circuits, but it's a mistake IMO, because the kitchen will often be heavily loaded, leaving no spare capacity for e.g. a space heater (when our boiler failed we used one) or vacuum cleaner.
 

Offline themadhippy

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Re: Ot: Dishwashers
« Reply #105 on: January 25, 2021, 11:04:42 am »

Quote
It seems to be now quite common in new UK homes to combine kitchen and downstairs circuits
Not really,older house and "cheap throw em up sell em quick" new builds then yea,but putting the kitchen on its own circuit is something thats been recommended for  a good few years.It was also not uncommon to put a  socket in just for the fridge and freezer on its own circuit that wasn't rcd protected, labeled "not for outdoor use",but now that everything has to be rcd protected thats no longer the case.
 

Offline madires

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Re: Ot: Dishwashers
« Reply #106 on: January 25, 2021, 11:13:45 am »
Over here the dishwasher is wired to the 3-phase outlet meant for the oven when there's no dedicated wall socket.
 

Offline themadhippy

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Re: Ot: Dishwashers
« Reply #107 on: January 25, 2021, 12:42:11 pm »
Quote
Over here the dishwasher is wired to the 3-phase outlet meant for the oven
As mentioned before,its pretty rare to find 3 phase in a uk domestic environment,they'd rather give you a single 100A supply than risk letting people loose with  415v.
 

Offline madires

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Re: Ot: Dishwashers
« Reply #108 on: January 25, 2021, 02:16:55 pm »
:) Yes, I know that ring circuits are standard in the UK. We're limited to 16A per chain which is the rating of the common breaker for households. So we have a 3-phase outlet for the oven, wired directly to the flat's distribution panel. No matter which method you're using, it's about getting the power needed to the outlet.
 

Online Ian.M

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Re: Ot: Dishwashers
« Reply #109 on: January 25, 2021, 02:22:44 pm »
In the UK, if use of an electric cooker is anticipated, its usual to provide a 32A or 45A radial circuit (240V) to a dedicated connection unit via an isolator often combined with a single BS1363 socket.

See https://www.tlc-direct.co.uk/Book/6.5.2.htm
« Last Edit: January 25, 2021, 02:27:31 pm by Ian.M »
 

Offline tom66

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Re: Ot: Dishwashers
« Reply #110 on: January 25, 2021, 03:41:54 pm »
In the UK, if use of an electric cooker is anticipated, its usual to provide a 32A or 45A radial circuit (240V) to a dedicated connection unit via an isolator often combined with a single BS1363 socket.

See https://www.tlc-direct.co.uk/Book/6.5.2.htm

It's also common to allow this 32A oven circuit to support a 13A plug and 9kW of hobs+oven,  I think it allows up to 11kW loading on what is a 7.2kW circuit, based on the assumption that no one will use all fully loaded at once.  But my mother had her microwave connected to the cooker socket which is one of those Panasonic 3kW convection-turbo ovens (I gave her my old one) which meant the cooker circuit breaker would clatter rather loudly when she was using that at the same time as the hobs!
 

Online Ian.M

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Re: Ot: Dishwashers
« Reply #111 on: January 25, 2021, 04:26:49 pm »
That's why there's a trend to either *NOT* provide a 13A socket on a 32A circuit or provide a 45A circuit, which always allows up to 7.8KW 'flat-out' for the cooker (or 10.8KW if 45A with no 13A socket), and as the rings and oven are regulated, usually by 'bang-bang' controllers, its rare to have all rings and the oven element drawing current simultaneously except for a few minutes during warmup if you turn them all on at the same time.

If course if the customer isn't a penny squeezing idiot, a reputable electrician doing a new install or replacing the feed cable, will probably recommend a 45A circuit breaker and 10mm2 cable, especially if a double oven cooker is to be installed or if an isolator with auxiliary 13A socket is to be fitted.  Use a long chain of contractors where you don't even get to talk to the electrician and haggle on the price and you'll usually get the bare code compliant minimum and occasionally a deficient bodge job with a bogus certificate.
« Last Edit: January 25, 2021, 04:33:02 pm by Ian.M »
 

Offline themadhippy

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Re: Ot: Dishwashers
« Reply #112 on: January 25, 2021, 04:33:16 pm »
Quote
It's also common to allow this 32A oveOver here the dishwasher is wired to the 3-phase outlet meant for the oven circuit to support a 13A plug and 9kW of hobs+oven,

The onsite guide to  the regs  gives a figure of 15kw  if protected by a 30/32A device which fits with the diversity allowed  on a cooker circuit which is  the first 10A of the rated current plus 30% of the  remainder and another 5A if a socket is built into the cooker control unit. One quirk, which is a throwback to the days of rewirable fuses, is the  use of 6mm2 for a 32A circuit, 4mm2 on a mcb is perfectly within the regs,but if  you dare to do it  every so called expert will be calling you a cowboy
 

Offline helius

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Re: Ot: Dishwashers
« Reply #113 on: January 30, 2021, 06:12:04 am »
I imagine it would work if there was sufficient W/m at the resist. Traditional exposers for resist materials were "actinic" arc lamps, which have very strong peaks at 355 and 385nm. The UV-C lamps made for disinfecting (they really are not designed to sterilize) in dishwashers etc may just not be strong enough.

You can see an arc lamp exposing resist on a printing screen in the classic "To Live and Die in L.A." directed by William Friedkin.
 


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