hot tub shut off from a safety switch


  #1  
Old 04-07-04, 10:12 AM
camien
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hot tub shut off from a safety switch

I am running a 50 amp disconnect for an outside hot tub. The home has 300 amp service that first goes into a safety switch panel and then continues on into the house to a main breaker panel. The breaker panel is completely full and is much farther away from the tub's location than the safety switch panel.

Question: Is it possible to run a disconnect off of the safety switch panel or do I need to run a sub-panel off of the main breaker box?

Thank you for any help.

P.S.- I have pictures of the safety switch panel (opened), but this site can not handle the size and won't except zip files. I can e-mail them to anyone that is interested.
 
  #2  
Old 04-08-04, 11:23 AM
W
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You are going to need to describe things more clearly. Are the pictures available on a web page somewhere (you can't e-mail them to me, sorry, server limits on my side).

If the outside 'safety switch' is in fact a main breaker panel (and what you call your 'main breaker panel' is actually installed as a subpanel), then you can legally have up to _6_ breakers in the main panel, all directly connected to the service. In this case, one of these could be the breaker/disconnect for the hot tub. However it may not actually be physically possible to install this breaker, and you will have to change out the 300A main breaker for a smaller size.

-Jon
 
  #3  
Old 04-08-04, 02:17 PM
camien
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safety switch

hey jon
 
  #4  
Old 04-08-04, 02:23 PM
camien
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safety switch

Hey Jon,

You can see the pics at:

bradgarrett.com\cam\DSC00163
bradgarrett.com\cam\DSC00164
bradgarrett.com\cam\DSC00165
bradgarrett.com\cam\DSC00166

4 links to 4 pics

The main power comes into the box (picture) from the top and terminates at a top lug, two fuses connect the top lug to the bottom, where the wires continue and run into the house to a 50 circuit load center(breaker box). The breaker box is full. I know that I could move a couple of circuits and the new disconnect into a sub panel, but the room is tight and is much further away from the hot tub (more money/more time). If possible, I would like to wire into the safety switch box and just put the 50 amp disconnect box beside it.

thanks for your help
 
  #5  
Old 04-08-04, 04:44 PM
camien
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links

Hi Jon, sorry, but on those links it should be:

bradgarrett.com/cam/DSC00163, 64, 65, 66, etc.

I put back slashes instead of forward slashes. sorry for the inconvenience.
 
  #6  
Old 04-08-04, 08:34 PM
W
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Hi Camien,

The other slashes worked fine...except that you left off the .JPG extensions on the file names.

In any case, what you have is a 'fused disconnect', and alas your situation is a beyond my experience level, so I am hoping that a couple of the professionals will chime in here.

It appears to me that the conduit is acting as your 'equipment ground conductor', however I don't think that the locknuts on the conduit connectors are 'bonding locknuts'; so this may be something that needs fixing by a professional, since it requires removing the service entrance cables. This is one of the things that I would like someone else to check on.

It is also necessary to determine where your 'ground bond' is. This is the point where the neutral wire is connected to ground, and is usually in the main panel, however it is allowed to be anywhere between the meter and the main panel. If your ground bond is in the meter, then you are fine, but if it is in your circuit breaker panel, then you have a problem that needs fixing. The fused disconnect is acting as your main disconnect, and the circuit breaker panel should be wired as a subpanel. I would suggest checking the circuit breaker panel and seeing if grounds and neutrals land on different bars or not.

If your ground bond is in the meter housing, and ground and neutral are separate in your circuit breaker panel, then I believe that you can run a _separate_ panel from the fused disconnect. This would require replacing the lugs connecting the wires to the breaker panel with lugs suitable for two wires. In general, these wires would need to be sized so as to be protected by the 300A fuses (pretty large wire), however 'tap rules' may come into play that would let you use smaller wires if the second panel were close enough to the main.

Something that concerns me is that fuses are being used for the main disconnect, and I wonder if you have a 'series rated' system. Circuit breakers need to be designed to be able to deal with the highest possible short circuit current which the power company can supply. If the short circuit current is high enough, then circuit breakers or fuses can literally explode rather than simply opening the circuit. Sometimes combinations of devices, eg. fuses and circuit breakers are used to permit circuit breakers with one rating to be applied on systems with higher short circuit capabilities. This is usually not a problem with residential systems, but something is making me wonder if... If this is the case, then you will need to be very careful in selecting the circuit breaker for the subpanel. It would pay to look for clues on the circuit breaker panel.

That's all that I have to add; let's see what others say.

-Jon
 
 

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