Grounding my MK5000 with 3 prong dryer outlet

[Jwolfrom80]

Sorry for the newby questions!

I am building an MK5000 to heat my boiler and am using a 5500 watt hot water heater element. The outlet I am intending to use hook into is a standard 3 prong U.S. dryer outlet (240v 40amp I think). The 3 prong plugs only have two hot 120v wires and a neutral... no (green) ground wire. So what do I do to ground this thing? I really don't want to feel that in my arm! I have tried to thoroughly read around here about the mulekicker 5000 and phase angle controllers, and can not find anything about how to ground this. My clothes dryer is running off this plug without any external grounding that I know of... and I don't get shocked with it of course. So how is this different and what should I do?

Thanks anyone who can help me! -Joe

[Dnderhead]

where you at,,and how many prong plug?

[Coaster]

@ Jwolfrom80,

The below referenced photo should explain the correct wiring for a 3 prong 220v Dryer Plug.



You should have 3 wires – Black (L1), Red (L2), and White (Neutral). In 3 prong 220v Dryer Plug the White (Neutral) wire serves as the ground.

Regards,
Coaster

[MuleKicker]

Coaster's pic is right. On the MK5500, you dont have a neutral, all you have is the 2 hot wires and a ground. Neutral is only used to make 110v. If you take one of the hot wires and return it to neutral, you get 110v. You dont need 110v with that controller.

[Dnderhead]

it depends on his plug he has. agreed he does not need neutral but it mite be on the plug.

[Prairiepiss]

it depends on his plug he has. agreed he does not need neutral but it mite be on the plug.

If it is just use it as the ground. The grounds and neutrals all tie together at the breaker box. At least all of them I have seen in houses around here do. Never quite understood that one?

[MuleKicker]

They do, but you arent suppose to do that. Im not saying you cant do it, just that we shouldnt tell people to do it. All circuits should be wired to conform with state and local electrical code.

[Dnderhead]

first the natural can be interrupted,,a switch etc. a ground cant it has to be continues.
next if the neutral is intrepid it could be energised back as far as the brake.

[Jwolfrom80]

I think it would be method 2... but I'm not 100%.. and is grounding the keg even neccessary?

And here is an empty just for fun!

Should I add a switch to break both hot wires (between the plug and pcm for red and between the plug and element for black)?

I just really want to be sure I get it right the first time, I've worked with electricity before, but nothing quite like this.
Thanks for your help!

-Joe

[rad14701]

Jwolfrom80, absolutely none of the above... Please wait until one of us can work with your blank copy...

[olddog]

Grounding is essential when electricity and a liquid are concerned.


OD

[Jwolfrom80]

EXACTLY! I realize the danger, that's why I'm trying to make sure its right. For some reason I cant wrap my head around this. The grounding/neutral thing is confusing me.

I am largely trying to model my build after the first one pictured at this thread (original post):
http://homedistiller.org/forum/viewtopi ... 46&t=17383
The picture with the box inside exposed is the one that looks like my method #2 drawing.. apparently I've missed something big.

And yes, I WILL wait. Thanks for the help

-Joe

[rad14701]

You want the wiring to be something more like this:

The green jumper wire is optional...

[Jwolfrom80]

So the pcm and pot don't get grounded (hooked to the neutral), just the keg and element? OK! Thanks!

[rad14701]

So the pcm and pot don't get grounded (hooked to the neutral), just the keg and element? OK! Thanks! I trust you!

No need to ground the pot but you should ground the PSR-25 (pcm)... If you were to ground the pot you would ground the case, but they are rarely ever grounded...

[Coaster]

@ Jwolfrom80,

Your PSR-25 should be wired as depicted in the below referenced picture ->

http://homedistiller.org/forum/download ... d=8173&t=1

Regards,
Coaster

[KY1792]

Heating element wiring 2a.jpg

As simple as it may seem this subject is always confusing, so lets clarify some things first (USA only)..

The outlet pictured in the 3rd post by Coaster is a Nema 10-30 and is a 125/250 hot/hot/ neutral configuration, it was meant to supply both 240v and 120v to the same appliance with no equipment ground. The outlet that you need would be a Nema 6-30 which is a hot/hot/ground which is only for a 240 volt appliance and equipment grounding. Coasters diagram is correct and me personally see no problems using it, but changing both the cord and outlet to 6-30 would be code.

Now to the neutral/ground busbar - if this is your main panel, a single neutral/ground bar is code compliant as long as there is a bonding screw in the bar to the panel. At no time can neutral (white) wires double up in a busbar hole but grounds (green-bare) can be 2 wires to a hole, if this is a sub panel then you need 2 busbars electrically isolated from each other.

You can also re-identify any wire except for a ground wire to serve a new purpose by wrapping a few inches of the appropriate color tape at both ends of the terminations. A black wire can act as a neutral by marking with white tape as a white wire can be used as a hot by marking with black tape, I never like marking a white wire with green tape unless it is a 240 volt use only as stated above - Nema 6-30. At no time can a green or bare wire be re-provisioned.

Also by code you can not break or switch a ground or neutral but not a bad idea to have one to open the 2 hots, for a 5500 watt element you would need a 30 amp / 240 volt 2 pole switch (23 amps).

[KY1792]

Sniped by Rad, guess my drawing skills need more speed and improvement.

Edit: I saw no need to ground the element as this is nothing but a simple water heater circuit with better control, the metal tank provides the ground for it.

[Jwolfrom80]

Excellent! It should be up and running by the end of the weekend!

Thanks!
-Joe

[rad14701]

Sniped by Rad, guess my drawing skills need more speed and improvement.

Edit: I saw no need to ground the element as this is nothing but a simple water heater circuit with better control, the metal tank provides the ground for it.

Gotta draw fast...

As for the element, yes, it gets grounded by the fitting in the boiler (keg)...


Also, some folks have had problems using pots rated under 2 watts even though the PSR-25 and other PCM's don't specify that high of a rating... However, the problems may have been related to cheap pots...

[MuleKicker]

I think the psr does call for a 2w.... If I remember correctly. But yes, cheap pots dont last. Newark sells a good one.
http://www.newark.com/jsp/search/produc ... ku=04F8770 Dont buy cheap pot.