Thread Number: 44443
Adding cord to dishwasher 		[Down to Last]

automaticwasher.org's exclusive eBay Watch:
scroll >>> for more items --- [As an eBay Partner, eBay may compensate automaticwasher.org if you make a purchase using any link to eBay on this page]
Post# 652708   1/12/2013 at 16:55 (4,114 days old) by aladude ()        

I recently bought a used portable ge dishwasher but its power cord was missing. I bought a replacement cord at lowes (16 gauge, 13 amp, 8 ft long) and connected white to white, black to black, and since the dishwasher was already grounded to the frame I just wired the green ground on the cable to the same screw where the ground was connected. It worked at the store with the same wiring setup but in my home it trips the gfi outlet every time I plug it in (knob turned to "off"). What am I doing wrong?




Post# 652789 , Reply# 1   1/12/2013 at 20:46 (4,113 days old) by Tomturbomatic (Beltsville, MD)        

Let me understand this. You took the dishwasher to Lowes and put the cord on it there and plugged it in at Lowes and it worked. Was the plug at Lowes a GFI-protected? GFI circuits are so sensitive that minute voltage leaks will trip them. The fact that the breaker trips even with the machine off is a clue that it is a voltage leak, I think. I think that if you try the dishwasher on a regular non-GFI circuit, you will find it works just fine. A regular ground will protect you from lethal shock. The source of the voltage leak can be anywhere, probably near the heating element. A 16 gauge cord is pretty marginal for a dishwasher or washer; 14 would have been better.

Post# 652835 , Reply# 2   1/13/2013 at 01:46 (4,113 days old) by aladude ()        

The one at Lowes was not GFI protected, at least not the type where the test/reset buttons are on the outlet itself. I checked the dial on wash, drain and dry portions and everything worked fine. My apartment does have the test/reset buttons on the outlet and the reset button pops out as soon as I plug the dishwasher in. I may have to try again with a better cord however.

Post# 652908 , Reply# 3   1/13/2013 at 08:59 (4,113 days old) by Tomturbomatic (Beltsville, MD)        

Are all of your kitchen outlets GFI-protected? You need to try it on an outlet that is not a GFI outlet.

Post# 652916 , Reply# 4   1/13/2013 at 09:35 (4,113 days old) by dj-gabriele ()        

May ask why isn't GFI protection compulsory on all the circuits?
That could lead to very unsafe situations if only a small electric leak is present

Post# 653005 , Reply# 5   1/13/2013 at 11:11 (4,113 days old) by bwoods ()        
GFCI locations

 In the U.S., the National Electric Code specifies that Ground Fault Circuit Interrupters be used in locations where it is more likely that a person's body may come in between an energized circuit and a grounding surface. Thus the individual is unwittingly becoming a path for current to flow to the ground

Kitchens, baths and outdoor receptacles are areas where a person may be grounded or touching a grounded surface, such as sinks, tubs, being barefoot outdoors, etc.

In the case of a ground fault, lets say a person is touching the metal body of a defective toaster which is leaking current and with the other hand they touch the faucet of a grounded sink. the current passes through their body in this ground fault situation. The GFCI will sense the imbalance and break the circuit.

In a bedroom or living room, the odds of a person being grounded out are much less likely, so the NEC does not require GFI protection in these areas.

Post# 653092 , Reply# 6   1/13/2013 at 15:44 (4,113 days old) by aladude ()        
UPDATE:

 I redid the wiring with different size wire nuts and a better gauge plug. It now works like a charm even in the same gfci outlet! Thanks for your help guys. It is strangely comforting to hear this machine churning away in the next room :) maybe it's because I know I won't have to do the dishes by hand anymore.

Post# 653098 , Reply# 7   1/13/2013 at 16:04 (4,113 days old) by dj-gabriele ()        

That's an interesting difference!
Here every circuit must be protected regardless of its location: it's strange because you could get a shock even in those non-wet areas, who knows; a curling iron, a malfunctioning steam iron, etc... :)

If the machine trips the RCD as soon as it is plugged in you could try measuring the resistance of the heater to the ground as it was already suggested, a partial solution could be reversing phase and neutral wires, it has mitigated the problem more than once with a steam iron of mine before I changed it.
Most probably you'll have to change the heater and the problem will be fixed.


Post# 653113 , Reply# 8   1/13/2013 at 16:25 (4,113 days old) by combo52 (50 Year Repair Tech Beltsville,Md)        
GFI Circuits ETC

 combo52's profile picture

GFI Breakers are unnecessary for appliances with three wire cords as you are automatically protected from a shock by a malfunctioning appliance.

 

  Refrigerators should not be used on GFI circuits unless you like the idea of coming from a vacation to a refrigerator that has shut down the GFI breaker with all you food rotting inside.

 

Heating elements in US DWs that have plastic tanks are usually not grounded, so it could not cause the GFI to trip, at least not until there is a water and detergent solution in the DW that could conduct power from a shorted element to a grounded part but even this is unlikely on most DW designs as usually no metal parts of the pump motors touch the water.
Post# 653129 , Reply# 9   1/13/2013 at 16:58 (4,113 days old) by bwoods ()        

Hi Gabriel,

It's not so much moist locations, as locations where the human body could contact a grounded surface and become a part of the current path.

GFCI protection does not work when a person is shocked by coming between the hot line and the neutral. Only when the GFCI device senses an imbalance between the current leaving the "hot" side and that entering the neutral will it kick out.

So let's say, in a living room, someone sticks their finger into a energized lamp socket. The current will enter the finger thought the hot contact and travel through the finger to the neutral. There is no current leaking from the hot side to a ground. So a GFCI, if it were in the circuit, would not sense anything and not kick out. So the person would feel a shock in their finger.

The NEC now requires another type of protection in dwelling bedrooms called "arc-fault" protection.

Arc Fault Interrupters (AFI) sense when electrical arcing (or sparking) occurs within a protected circuit. For example, when a wire comes loose from the screw terminal of an outlet inside of a junction box. Oftentimes, home fires are caused by this type of arcing as the heat generated can start a fire within the wall.

The NEC committee felt the greatest danger is within the bedrooms of a dwelling as the occupants may be asleep and succumb to the smoke or flames.

Post# 653217 , Reply# 10   1/14/2013 at 04:16 (4,112 days old) by dj-gabriele ()        

That's interesting to know all those differences.
From the engineering point of view years would be needed to discuss everything and I'd love to! As I'd love to know the why of all these differences.

As an example I've seen that there's a law for which bread toaster MUST not be grounded in the US! Here is compulsory to ground them because they're not double insulated appliances and shock protection is done via very sensitive RCD devices like 10 or 30 mA on the cicuit! Same goes for fridges, in fact auto-restarting ones are becoming very common, they turn themselves back on if they sense that there's no danger on the circuit.

Not grounded heaters in dishwashers:
it might make sense in plastic tub machines but over here the chassis and tub are all made of stainless steel so grounding is a must, should the heater start to "leak" (humidity penetrating the magnesium oxide shell), even a few milliamperes of dispersed current will trip the GFI protection.

As an example it happens with my washer dryer when it starts drying: there's a resistance on the megaohm range between earth and phase in the drying element, the leak current is so small that even touching the cabinet with the machine running with earth disconnected you can't feel it but yet, it's enough to trip differential protection. Till I'm getting replacement heaters (bless Candy group that have spares after 27 years!) I just run the machine disconnected from eath but it indeed is a potentially very dangerous situation.

Also should be noted that ours is a TT system so earthing protection is compulsory for the system to run safely compared to ones with insulated circuits or those with neutral and earth linked together at the junction box.

Anyway, I want to cite this:
"s say, in a living room, someone sticks their finger into a energized lamp socket. The current will enter the finger thought the hot contact and travel through the finger to the neutral. There is no current leaking from the hot side to a ground. So a GFCI, if it were in the circuit, would not sense anything and not kick out. So the person would feel a shock in their finger."

It would be so only if one is standing on an insulating surface and not touching anything else besides the bulb socket. Such a shock could lead to tetanization of the arm muscles and a potentially no-let-go situation.
In a system where the lamp body is connected to earth or in case of conductive ground (tiles, marble, etc) a small current would pass on the body and trip the RCD almost instantly.

I still remember the discussion we had a few years ago, it was most interesting and I'm glad we're coming back on this topic! :)

Post# 653219 , Reply# 11   1/14/2013 at 05:38 (4,112 days old) by bwoods ()        

It is interesting! Yes, there could be possibilities were one could be grounded, even in a living area. In the U.S. our table lamps are not generally grounded so I used that just as an example. At least, at this point in time, the NEC is just requiring areas to have GFCI protection where the probability of grounding out are the highest.

It appears that Italy has a much more conservative approach to ground-fault protection. I assume you have a national electric code, similar to the U.S. NEC.

What are your residential voltages in Italy, Gabrielle? In the U.S. residential voltages are 110-120 and 220 - 240 at 60 hertz (cycles per second) frequency. Lamps, small appliances, electronics are generally 110/120. Larger appliances such as ranges, dryers, HVAC are typically 220/240 v.

Most residential systems do not have isolated grounding. The ground and the neutral are not joined in the wall junction boxes, but they are generally connected within the main central panel box (breaker box) with the neutral and grounds often on the same buss. The buss is grounded, not only at the utility pole, but the NEC requires each residence to have a earth buried grounding rod also attached to this buss.

Prior to the 1990's most 240 volt devices, like ranges and dryers, did not have a separate ground and had a 3 wire connector (2 hot legs and a neutral) with the metal chassis of the device being connected directly to the neutral by a removable grounding strap.

The NEC, for added safety, now requires some residential appliances, like electric stoves and dryers, to have four conductor connections with a separate ground (or earthing) connection. The ground and neutral, however, may still be connected within the central breaker box.



Post# 653227 , Reply# 12   1/14/2013 at 06:08 (4,112 days old) by dj-gabriele ()        
much more conservative approach to ground-fault protection

 It indeed is because of the TT system, each building has its own earth pole and the utility company only supplies 4 cables for 3-phase and 2 cables for single phase users. It offers improved resilience over disturbs on the line but also opens a path where ground has low resistance so interrupters have to be very sensitive. Neutral is ALWAYS separated from the ground/earth wire, this offers vastly increased protection in case of broken neutral which can be a common issue in other countries.

Standard is 230V phase to neutral at 50Hz like elsewhere in Europe, with powers of up to 10 kW single phase and three phase (400V phase to phase, 230V p-to-n) over that, of course one can request even a 1,5kW contract in threephase (as an example in country grounds where only a water pump can be used!)
The most common residential contract is 3 kW at 230V monophase. 6 and 10 kW contracts are sought after those wanting induction cooking or heat pump heating but they are charged at a premium rate to incentive low consumption. (Electricity here is the most expensive of all the OCSE nations!)
The only domestic appliances using threephase current are induction cookers and centralized air-conditioners but both can be had to run on single phase albeit requiring much thicker wiring and in the case of A/C at a little lower efficiency.

A single "normal" socket circuit supplies 16A and is protected with a 30mA RCD and has overcurrent and shortcircuit protection (thermal and magnetic protection), if supplying a "delicate" appliance like a freezer or fridge the switch can be of the self-reactivating type to prevent energy loss in case of accidental tripping.
For increased safety bathrooms are generally protected with 10mA RCD and supplemental electronic protected wall outlets are not uncommon at all (such in case the bath is on a 30mA protected circuit one adds a 10mA additional protection).
All the light switches and sockets are modular so one can assemble what he needs in predefined forms in a mix-and-match system, something I've yet to see elsewhere like in France or the UK!

The residential systems are defined under the CEI64-8 norm, the degree of standardization is such that they even mandate the number of sockets and circuits for each room/house size, destination and place, besides the minimum requirements, so on that aspect I'm most satisfied!
Fault and shock protection is mandatory since the 60s, can't remember the law number but is quite old and was renovated quite a few times.
As an example I have never seen a fused circuit in all my life even in old (60s) installations as MT and MTD (magnetic+thermal+differential protection) was the norm.
Only industrial/commercial users had fuses on large current circuits but even in these applications MTD interrupters are the norm now.

CLICK HERE TO GO TO dj-gabriele's LINK
Post# 653248 , Reply# 13   1/14/2013 at 10:42 (4,112 days old) by bwoods ()        

The differences in the electrical systems are fascinating. The GFCI was not required by the NEC, in residential dwellings, until the early 1970's. However, fuses were phased out in new home construction in the very early 1960's by MT prtection devices (we call them "circuit breakers".)

In U.S. residential wiring the ground and the neutral may not be connected or allowed to conductively touch anywhere in the circuit up until the conjuncture in the main central panel box. That way is there is a break in the neutral anywhere in the circuit, there is always an alternate path for current flow.

However, I have always been a big proponent of an isolated ground for the very reasons you mentioned. Most panel box manufacturers in the U.S., like General Electric (GE) have convertible main breaker panels which allow for connection of the neutral buss and ground buss, or they may be electrically separated for an isolated ground system.


Even though not as often utilized in residential installations, isolated grounds are required in many commercial applications, such as hospitals.



Post# 653257 , Reply# 14   1/14/2013 at 11:27 (4,112 days old) by dj-gabriele ()        

From what you said it seems that you're using a TN-S earthing system!
Ground and neutral are connected only near the transformer or anyway outside the premises of the final customer.

IT systems are used here too in "sensitive" hospital circuits but they're not the norm everywhere.

What amazes me the most is how "huge" the electric service is in the US compared to Italy, I've seen that most are around the 100A range and some are 200A, is that at 120 or 240V? Either way it's quite a lot of power delivered to a single dwelling ;)

Go figure that my father's laundry has a 17kW contract at 400V 3PH! That's just less than 25A!

Post# 653321 , Reply# 15   1/14/2013 at 15:42 (4,112 days old) by bwoods ()        

Ours may be huge, but it appears Italy's systems is much more sophisticated. Even outside of dwellings our power grid is aging and is in need of updating. It is only slowly starting to happen with the gradual changeover to a "smart grid."

In the U.S. system the ground and neutral may be connected within the customer's premises, but only at the main panel box which is the point of entry of current directly from the utility's power meter.

Many new dwellings in the U.S. are now 200 amp service @ 240 volts. It is the norm if the dwelling utilizes electric heat or heat pump. If the HVAC is fossil fueled, occasionally the service may be 150 amp, but many times 200 amp is used anyway due to central A/C. One reason for the high ampacity of U.S. homes is the popularity of electric hot water tanks, electric dryers and electric ranges. If the homeowner has these three devices electrically powered and then adds electric heat, central A/C or a heat pump, then 200 amp service is not overkill.

Sometimes homeowners also have other high current devices such as central vacuum, arc welder, air compressor or other shop tools. So it pays to have a little excess ampacity and this may serve as a positive selling point when the house is marketed.

Post# 653324 , Reply# 16   1/14/2013 at 16:10 (4,112 days old) by dj-gabriele ()        
little excess ampacity

It'd be great to have it! :)
Even 6 kW are a luxury according to most, to me they're a necessity, our A/C and oven alone are more than 3kW each... otherwise one couldn't turn both on at the same time! And forget doing the dishwasher while cooking and running the washing machine :D but this has been the norm since ever and now that we went for the no-nuclear way a second time, things won't surely change!
Go figure that running a contract over the standard baseline 3 kW will cost (in the case of a 6kW one) some 15€ per month more JUST TO HAVE IT, regardless of the real power consumption! And electricity will be more expensive too with the basic plan with free market offering little to none advantage.

(Oh, btw, electricity retails at around 0,27€/kWh now, it's like 0,37$ with a possible raise on the next billing cycle! That's why people value electric efficiency so much) :S

Post# 653346 , Reply# 17   1/14/2013 at 17:28 (4,112 days old) by kb0nes (Burnsville, MN)        
Defective plug?

 kb0nes's profile picture
The only guess I have is that the stock molded plug on cord you bought was somehow leaky. Provided your connections in the unit were solid and clean replacing that end probably didn't fix the problem.

I have seen the molded end of a cord fail several times, although they usually failed open, not shorted in anyway. When the cord end was molded its possible that something could have allowed a small current path inside the plug. It takes very little current to trip the GFCI, I think the test standard is .05 amps.

I often lop off the molded ends of cords and replace them with a good reusable plug/socket (good is Leviton, Hubble etc). Especially for any high current applications. The molded plugs sometimes get hot and burn up when used in high current applications. Another benefit is if the cords are used somewhere cold. On the female end of extension cords the molded plastic gets hard in the cold. In MN winters you can't plug your engine heater into an extension cord well below zero sometimes!

Post# 653465 , Reply# 18   1/15/2013 at 06:31 (4,111 days old) by Tomturbomatic (Beltsville, MD)        
Phil

 Frigidity causes rigidity.

Post# 653853 , Reply# 19   1/16/2013 at 23:41 (4,109 days old) by kb0nes (Burnsville, MN)        
Tom

 kb0nes's profile picture
and shrinkage...


Forum Index:       Other Forums:                      


Comes to the Rescue!

The Discuss-o-Mat has stopped, buzzer is sounding!!!
If you would like to reply to this thread please log-in...

Discuss-O-MAT Log-In



New Members Click Here To Sign Up.



                     

automaticwasher.org home
Discuss-o-Mat Forums
Vintage Brochures, Service and Owners Manuals
Fun Vintage Washer Ephemera
See It Wash!
Video Downloads
 Audio Downloads
Picture of the Day
Patent of the Day
Photos of our Collections
The Old Aberdeen Farm
Vintage Service Manuals 		Vintage washer/dryer/dishwasher to sell?
Technical/service questions?
Looking for Parts?
Website related questions?
Digital Millennium Copyright Act Policy
Our Privacy Policy