Electrical question.

[Kali]

Not sure asking this on a Friday night in the lounge is the best idea but what the hell:

We have slowly been rebuilding an old hot tub (hope to have it done before summer!) and are ready to change out the electric stuff. We are putting a new GFCI box near the new controller. This first picture is the instructions for installing. I understand it completely - NO PROBLEM so please move on to the second picture.




This is a little bag that came with the box. Do I need this? It is NOT in the picture above, or with anything else I can see in terms of instructions, and it does say "When bonding is required" so obviously it isn't always required. (Just when is it required???) It also looks like it just ends up grounding the neutral wire back to the box - WTF?



I know, I know - if I don't really understand it I probably shouldn't play with electricity but I have never let the fact that I'm not qualified stop me before so I ask the great DU wisdom: Do I need to hook this little strap thingy up?

[leeroysphitz]

1. I think that component is responsible for reversing the polarization

of the non-phased isolinear alignment grid. You should use your interocitor to see if it contains a magnetic dipole.

[Kali]

3. cool! thanks!

:rofl:

[redqueen]

2. This might be helpful...

http://www.hep2o.co.uk/bititesguideearth.htm

At the Service Position - Main Bonding

In each electrical installation, main equipotential bonding conductors (earthing wires) are required to connect to the main earthing terminal for the installation of the following:

metal water service pipes
metal gas installation pipes
other metal service pipes and ducting
metal central heating and air conditioning systems
exposed metal structural parts of the building
lightning protection systems

It is important to note that the reference above is always to metal pipes. If the pipes are made of plastic, they do not need to be main bonded.

If the incoming pipes are made of plastic, but the pipes within the electrical installation are made of metal, the main bonding must be carried out. The bonding being applied on the customer side of any meter, main stopcock or insulating insert and of course to the metal pipes of the installation.

[Kali]

6. so that sounds like I don't need it - right?

the box is mounted on wood and the plumbing is all plastic

(gotta say some of that sounds like the post above - maybe that wasn't nonsense after all???)

[redqueen]

7. I dunno. I'd do it anyway...

cause I'm paranoid like that. :P


And no, the post above is pure-D BS. :)

[Kali]

10. Me too - I'm so paranoid that I'm worried if I don't need it

and put it in anyway that it might fuck something up!

[MajorChode]

17. You really want to look all around the tub for metal objects...

in addition to the ones mentioned. In theory, even if you do have non-bonded metal objects nearby there should be no potential for electrocution because the GFCI will trip within milliseconds if there is a ground fault.

Wiring up everything yourself is fine, but you really should consult a local licensed electrician and have them inspect your work before you throw the juice to it. They will be knowledgeable of the local electric code requirements. You'll pay a fee for a housecall and that's it. It's money well spent for peace of mind if nothing else.

[petronius]

4. When it's my own house that's likely to go up in smoke, I consult an

electrician (or the old dude at the hardware store). Since it's only your house, I'll happily give advice: call an electrician!

:shrug:

[Kali]

8. I'm too far away and too cheap.

Also it isn't connected to the house so I think we can get the fire out with the water from the tub, right?

Old dude at the hardware store is a possibility, though. Might even have to go to town tomorrow.

[flvegan]

5. I have no idea what ANYthing in this OP means. At all.

Well, the circuit breaker is off. I got that far.

[Kali]

12. Admittedly I have the actual objects available to look at, plus the old instalation

AND I have been staring at it all off and on since x-mas. Just finished the plumbing - that took a long time too. Fracking 2" schedule 40 is hard to cut into small pieces with a dull pruning saw.:rofl:

The problem is the old one didn't have a GFCI - that is how old it was - oops.

[struggle4progress]

9. You don't want to serve as the conductor between two different nearby objects

http://en.wikipedia.org/wiki/Electrical_bonding

[Kali]

14. well that kind of confused me

it is separate from the house and on its own circuit. No water line directly to it (will fill with a hose) it is aobve ground (technically a "portable" though it is pretty damn heavy) although it is on a concrte slab that is reinforced...???

Reading that is sounded like I didn't need to do it until the end when it was talking about pools and fountains.

[struggle4progress]

19. I think the possible issue is electrocution, and the hazard may depend significantly on details

of the construction

See e.g. this discussion: http://forums.mikeholt.com/archive/index.php/t-91074.html

If I were doing this in an area where a permit wasn't actually required, I'd still try to ask somebody familiar with standard electrical codes about grounding and bonding ideas

[ornotna]

11. No, you don't need it

Provided there is a separate ground bar like the first drawing shows.

[Kali]

13. I kind of didn't think so.

But what is it for then? The neutral is insulated from the box, and the ground isn't so why would you want/need to ground it?

And thanks!

[ornotna]

15. It's a neutral bonding jumper

and is only done at the service entrance (main panel board). You do have 4 wires feeding your GFCI box correct? 2 hot wires, a neutral and a ground. If so, you'll be fine. just make sure your connections are tight.

[Kali]

16. yes, have all 4

again, thanks. So, what if I did it anyway? Would that mess something up? Obviously I am not getting the difference between ground and neutral, or maybe I am making too much difference?

[ornotna]

18. You might get a severe shock

You would set up a parallel path for neutral current to flow through the case of the gfci box, if it's metal.

[Jamastiene]

20. National Electrical Code

Ok.

The neutral IS a current carrying conductor. It takes the current from the hot side back to the power line. The only reason the neutral is named different than the hot is to let you know that the neutral is the one that is ground(ed).

Just remember:
The Neutral is ground(ed).
The ground is the ground(ing) connection.

The ground is there for the purpose of protecting you (and your home, appliances, structures, etc.) in case of a ground fault condition. What that means is that if the hot wire should come into contact with metal parts of appliances, you want that breaker to trip, and that includes the GFCI. That's what the ground does in the GFCI; it triggers the breaker to trip if it has a certain set amount of current running through it, depending on the amperage of the GFCI.

That's why you need a ground in a 3 wire setup. You have your hot to bring the current in, the neutral to take it out and the ground to protect you and your home in case of a short of hot to any metal parts of the appliance.

In a ground fault condition, without proper ground(ing), if a hot conductor should come into contact with any metal parts, then YOU come into contact with any metal parts, let's just say it'll hurt really really bad...if you live.

Me? I would bond it.

All bonding does in this case is creates a stable potential (no difference of potential) between any metal parts you may come into contact with. In other words, if the drain is metal and it is bonded and the faucet is bonded and any other metal parts are bonded, they create their own circuit of nothing, no potential difference. No potential difference means no current and no frying while submersed in water.

Read this:
http://ecmweb.com/mag/electric_grounding_vs_bonding_11/

It will help you understand it much better than I can explain. It gets hairy with all the "ed" and "ing" and all that jazz.

[conscious evolution]

32. Some jurisdictions require

ground/nuetral bonding in the panel box.
You can tell by whether the service entrance cable. has three or four conductors.Sounds like you have four and they are most likely bonded at the meter center.In that case you don't need it,provide you follow all of the other grounding instructions.

[Mugu]

21. I don't see what the problem is here.

The issue in the second photo is simply tying neutral to ground so you can't end up with a floating neutral (neutral that is above or below ground potential, thus in itself a shock hazard.)

A GFI protects from hot to ground, not neutral to ground or hot to neutral.

Just install the jumper between neutral and ground and then install the GFI as pictured. No problem. There's a good chance that there is already a tie installed between ground and neutral in your breaker box that you haven't seen. Just use your ohm meter and the existence of the tie should become obvious.

If you don't have a VOM you should probably hire somebody.

[Kali]

23. I guess what I don't understand is

why even have a separate ground bus? The neutral bus is insulated from the box unless that strap is installed. So why not just have the neutral bus attached right to the box (or the ground)?

Sorry to be so obtuse, electricity comprehension for me veers into the realm of magic - I don't get it. I can follow instructions but the ones for this part seemed non-existant in the materials that came with the equipment. (and it seemed wishy washy with the "when required" statement)

The main box coming into the back of the house has the bonding strap thing installed - just went out and looked (and see the husband pulled the breaker for the hot tub's line all the way out (we is skeered of this stuff - ha)

I actually have two meters! Mice chewed the leads for my original, but I couldn't find any replacements so I recently bought another. Not that I really have a clue what any of it means, but again I can follow directions if they are written in actual English.:rofl:

[Jamastiene]

26. Sigh

I wish you the best of luck. Please try to stay safe. Let me know when you throw the juice to the hot tub, so I can :hide:


:P

[Kali]

27. We have to repair a pipeline before I can even fill the darn thing!

It will be a while. Meantime nobody has explained why the neutral bus is insulated unless you install that thing. Why have the option? That is my current (ha ha) confusion.

[ornotna]

31. Please read the second sentence in the link

http://www.mikeholt.com/mojonewsarchive/GB-HTML/HTML/ProperNeutral-to-Ground-Case-Connections~20021206.htm


Like I said up thread, not needed. You should only bond the neutral at the service.


Those test subjects of yours would grow up to hate you, if they grow up.

[Kali]

33. thanks for that

I think that is the ticket, alright. Service panel is already bonded, this is just a sub and the only breaker in it is the cfci for the tub. No metal to speak of (still a little leery about the reinforcing in the slab, but I think it will be alright, nothing structural is touching it that is conductive.

[ashling]

22. You might want to get out of the tub

before making the connections. That's about it for me :shrug:

[madinmaryland]

24. Note to self: NEVER GET in the hot tub at Kali's house!!

:hide:

[Jamastiene]

25. Could you please move your hand?

I would like to copy your notes. Something tells me this is not going to end well. Kali was good whilst we knew her. I'll sure miss her. :(

[Kali]

29. ah hell,I have at least three test subj - er I mean kids! I'm not going anywhere.

:evilgrin:

[Jamastiene]

30. .

:spray:

:rofl:

[Kali]

28. Just make sure someone else goes first!

That is my philosophy:rofl:

All I can say is you should have seen this thing before! And when we first moved here holes in the tin on the garage glowed! We had a real electrician come re-wire most of the place but we couldn't do two rooms in the front of the house because my Grandfather was so senile, yet had a gun! Wheee that was fun. One circuit in the living room must be 70 years old or more. When did they invent electricity? His dad was pretty progressive and probably had the house wired as soon as it was available. Grampa, on the other hand, rarely change anything.