Does this device exist?
 

Does this device exist?
 

In article ,
says...

They are available here in the Netherlands, and are/were commonly used
to connect a washer and a dryer to a single circuit.
These boxes cover the same situation, where a washing machine consumes
a lot of power during the phase where it heats the water and could trip
the breaker when a dryer which also uses a lot of power is used at the
same time.



Interisting. I guess where you are at the circuit is around 240 volts
for everything.

Here in the states most washers use 120 volts and the dryers are on the
240 volt circuit. That way they can be ran at the same time as the
wires go back to the breaker box.

I don't know how others do it,but many days my wife will wash 2 or 3
loads of cloths. She will be drying the first load while the 2nd one is
washing to save time.

Does this device exist?
 

On Wednesday, 2 October 2019 13:02:17 UTC+1, wrote:
On Wednesday, October 2, 2019 at 6:58:54 AM UTC-4, tabby wrote:

such demand management is perfectly legal here.

The US has three levels of "management" for electrical (and other) devices:

a) The National Electrical Code (NEC): This regulates hard-wired systems and switchgear, and how peripheral devices are connected to the system - such as light fixtures and other devices not plugged in. A hard-wired relay would be considered "switchgear" and therefore covered.

b) UL (Underwriters Laboratory) - this is a 'family' of such bodies, of which UL is the most prevalent: UL regulates those devices that connect to the system above, and has to do with (among many other things) grounding, electrical safety, loading, and so forth. This applies to stand-alone (complete) devices. Note that such devices are "LISTED", not "approved".

c) UR (Recognized): This applies to individual components within a system - such as a relay in a control, or similar. That part does not stand alone.. but may be replaceable. So, if one has a UL device of several parts, one fails, then that part *must* be replaced with a UR part to retain the UL listing.

Why it matters: There is this funny thing called "insurance". And if one has property insurance, and reads the fine print, it will refer to things meeting code and being properly inspected and so forth. It will also refer to 'connected devices' or any number of other words for whatever one has to plug into the wall as being "listed".

Should that hand-made relay you are referring to cause a fire and cause damage such that the property owner makes a claim - and should the insurance inspector (and there will be one) determine that the cause was this unlisted/unrecognized device - OOPS! Either the Company will not pay, or if it does, it will then immediately cancel the policy. And the property owner will be quite challenged to get insurance in the future at any reasonable cost..

Nothing that was done was "illegal". And Code Violations are not "illegal".

Just stupid. Something you continue not to understand. And the advice you give continues to suffer for it.

Peter Wieck
Melrose Park, PA

of no relevance to us here in the UK.

Does this device exist?
 

On Wednesday, 2 October 2019 13:47:23 UTC+1, Wolfgang Allinger wrote:
On 30 Sep 19 at group /sci/electronics/repair in article
tabbypurr wrote:
On Monday, 30 September 2019 16:47:15 UTC+1, wrote:
My brother's wife wants a small water heater under the kitchen
sink. Not an instant hot water type but one that holds a couple
gallons.
There is a receptacle under the sink but it also powers the
diswasher. I am concerned that if both the dishwasher and the water
heater are on at the same time it will pop the breaker.
I am looking for a device that will allow the water heater to be on
until the diswasher starts drawing a certain amount of current, at
which point the power to the heater would be turned off.
The power to the dishwasher needs to be on all the time, only the
heater should be switched. A switch for the water heater cannot be
added. The solution needs to be plug and play and require no input
from anyone using the diswasher.
It seems to me that something like this must be available but I
can't think of what it would be called and my brain is apparently too
fuzzy this morning to get google to come up with something for me.
I am willing to build the device myself if need be but a purchased
product would be better.
Thanks,
Eric

A relay is all you need. Remove the coil & rewind with a small number of
turns of thick wire. Now when enough current goes to the dishwasher, the
water heater is turned off. I'd use 2 relays the same, one to experiment,
the 2nd for the final unit.

No, it wouldn't work. Normal relays working with DC coils. You need a very
special relay designed for AC coils. Very rare and likely expensive.

Contactors exist for AC and DC coils, maybe they work. You need one with
contact type NC i.e. closed for feeding the heater when no current is
drawn from the dishwasher. These NC types are not common too.

Relays with ac coils are common. Some are called contactors. And relays/contactors with 2 way contacts are also common.


NT

Does this device exist?
 

On Wednesday, 2 October 2019 21:22:21 UTC+1, Ralph Mowery wrote:
In article ,
says...

They are available here in the Netherlands, and are/were commonly used
to connect a washer and a dryer to a single circuit.
These boxes cover the same situation, where a washing machine consumes
a lot of power during the phase where it heats the water and could trip
the breaker when a dryer which also uses a lot of power is used at the
same time.



Interisting. I guess where you are at the circuit is around 240 volts
for everything.

Here in the states most washers use 120 volts and the dryers are on the
240 volt circuit. That way they can be ran at the same time as the
wires go back to the breaker box.

I don't know how others do it,but many days my wife will wash 2 or 3
loads of cloths. She will be drying the first load while the 2nd one is
washing to save time.

If it really is just the drier that's the problem, there are better ways to dry things anyway, eg fan & dehumidifier.


NT

Does this device exist?
 

Does this device exist?
 

On Monday, September 30, 2019 at 8:47:15 AM UTC-7, wrote:
My brother's wife wants a small water heater under the kitchen
sink. ...
There is a receptacle under the sink but it also powers the
diswasher. I am concerned that if both the dishwasher and the water
heater are on at the same time it will pop the breaker.

Breakers (thermal type) can tolerate a short-duration overcurrent, so all you really
need is a low-voltage AC relay, coil in series with... the water heater.

Problem: if it turns off the dishwasher, does the electronic controller forget that
it was in a cycle, or on a timer, and stay OFF? Old dishwasher controls (cam
and motor) would continue after interruption.

Turn it around the other way, and sense current into the dishwasher, turning off
the water heater... but the dishwasher has a complex cycle, not a constant current
at all, how would you know the right current-draw threshold?

It can be done, but running another circuit to the kitchen is easier. While you're
at it, see if 240V heaters are available, the wire won't have to be as heavy...

Does this device exist?
 

Ralph Mowery wrote:
In article ,
says...

They are available here in the Netherlands, and are/were commonly used
to connect a washer and a dryer to a single circuit.
These boxes cover the same situation, where a washing machine consumes
a lot of power during the phase where it heats the water and could trip
the breaker when a dryer which also uses a lot of power is used at the
same time.



Interisting. I guess where you are at the circuit is around 240 volts
for everything.

Here in the states most washers use 120 volts and the dryers are on the
240 volt circuit. That way they can be ran at the same time as the
wires go back to the breaker box.

I don't know how others do it,but many days my wife will wash 2 or 3
loads of cloths. She will be drying the first load while the 2nd one is
washing to save time.

Here we have 230v line for all purposes (except industrial stuff which
users 3x230v 3-phase, 400v between phases).

The problem would only occur in older installations where there is only
a single circuit of maybe only 10A. Nowadays all circuits in homes
are 230V/16A. So you can use a total of 3.6kW which should be enough,
or else you could have 2 circuits. Main fuse is usually 35A.