how flexible is this circuit breaker

Reply

  #1  
Old 01-30-10, 10:15 PM
B
Member
Thread Starter
Join Date: Feb 2005
Location: seattle, wa
Posts: 98
Received 0 Votes on 0 Posts
how flexible is this circuit breaker

I would like to hook up a basic arc welder in my garage, I think it draws no more than 80 amps.

Here are some pics of my setup:






Now, from what I can tell, this breaker is fed by 10 gauge wire, and so I'm thinking there is no way for me to hook up an arc welder that could draw almost 80 amps.

Unless it would be okay to make a 240v outlet, or would those 10 gauge wires not handle that?

I'm thinking no, with this particular breaker box, and those particular feed wires.
 
Sponsored Links
  #2  
Old 01-30-10, 10:32 PM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,597
Received 13 Votes on 11 Posts
Well to start with that isn't a breaker box. It is a very old fuse panel with after market screw in breakers.Is 80 amps the output or input. If it is the input there is no way it is 120v and no way #10 wire will work. Is that a subpanel in the picture? If this is a sub and your main panel is similar I doubt your service could handle a welder that size.
 
  #3  
Old 01-30-10, 10:50 PM
B
Member
Thread Starter
Join Date: Feb 2005
Location: seattle, wa
Posts: 98
Received 0 Votes on 0 Posts
thanks for the reply. Yes, this is an old fuse pannel. It's fed from a newer box at the main house. The main is rated at 200amps, and the breaker that goes to this panel is rated at 30 amps.


This one is in the garage.

80amps is the output. This is the model I was considering:

Harbor freight

Originally Posted by ray2047 View Post
Well to start with that isn't a breaker box. It is a very old fuse panel with after market screw in breakers.Is 80 amps the output or input. If it is the input there is no way it is 120v and no way #10 wire will work. Is that a subpanel in the picture? If this is a sub and your main panel is similar I doubt your service could handle a welder that size.
 
  #4  
Old 01-30-10, 11:02 PM
B
Member
Thread Starter
Join Date: Feb 2005
Location: seattle, wa
Posts: 98
Received 0 Votes on 0 Posts
may have answered my own questoin

If this fuse panel is being fed by a circuit that has a 30 amp breaker, then that is the limit of this fuse panel, right?
 
  #5  
Old 01-31-10, 12:07 AM
F
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,495
Received 35 Votes on 27 Posts
In your first picture you show the label for the fuse panel and it states 50 amperes at 240 volts. That means that with the proper supply conductors the maximum amount of amperage that panel can supply is 50 amperes at 240 volts. For all practical purposes that panel was originally intended to have #6 supply conductors fed by a 60 ampere fuse or circuit breaker and all the branch circuits would be limited to 15 amperes.

With the #10 supply conductors the panel is limited to 30 amperes. Looking at the instruction manual for the linked welder it states an input of 20 amperes at 120 volts so depending on the load already on this fuse panel you could add a single 20 ampere, 120 volt circuit to serve the welder.

There is at least one thing wrong with this installation according to current electrical code and that is the connection of the equipment ground wires (bare copper wires) to the neutral bus. While this may have been acceptable when the panel was installed it is a safety hazard. If the conduit containing the supply conductors is continuous back to the Service (main) panel then the conduit serves as an equipment ground and the equipment grounding conductors could (at least theoretically) be removed from the neutral bus and then connected to the steel case of the panel by one of several methods to improve safety. If I am correct in my thinking the round-head machine screw in the middle of the neutral bus is a bonding screw and if you convert to a isolated neutral and proper equipment ground that screw would need to be removed to isolate the neutral from the steel case.

Is this garage attached to the house or is it a separate building? If a separate building then to bring it to current code you would also have to have a ground rod (or two) connected to the steel case.

It also appears that the supply conduit contains a type NM cable rather than individual conductors. While this is permissible under some conditions it is not considered best practice. Depending on the size of this conduit you might be able to remove the cable and substitute larger individual conductors giving you greater capacity.

Ray, there are no "aftermarket screw-in breakers" visible, only two standard plug fuses. It also appears that at one time a heavy load was connected to the left middle fuse as indicated by its discoloration.

Briholt, in my opinion you would be far better off to replace this panel with a 60 ampere rated circuit breaker panel. The cost, including breakers (but not professional labor), would be less than $100 depending on the distance from the Service panel and whether or not you chose to replace the feeder cable with individual wires. It would make a far safer installation and likely give you greater capacity.

One last thing, those Harbor Freight welders get almost universally condemned for poor performance. Unless you are already a skilled welder you would likely become extremely frustrated in using that HF machine to learn to weld.
 
  #6  
Old 01-31-10, 12:31 AM
B
Member
Thread Starter
Join Date: Feb 2005
Location: seattle, wa
Posts: 98
Received 0 Votes on 0 Posts
Furd, I really appreciate your thoughtful post.

This garage is not connected. It's about 100 feet away, and the wire is underground. I wonder what it would take to get a bigger feeder line.

Your estimate for upgrading this fuse panel makes me happy. My dad is currently building his own house and is doing all the electrical work. I'll see if I can get his input in upgrading this thing.

I've always been a bit worried about this box and so hearing that it would be a relatively cheap upgrade I'll look into this.

As for the welder, I sort of figured that it isn't a high quality welder and I'd only be using it for very minor/small projects. But I will certainly heed your advice.
 
  #7  
Old 01-31-10, 07:54 AM
W
Member
Join Date: Feb 2006
Location: USA
Posts: 6,706
Received 17 Votes on 16 Posts
Electrical Specs

Look at the manual available for download on the HF website for this item. Page 2 has the electrical input requirements.
 
  #8  
Old 01-31-10, 10:42 AM
B
Member
Thread Starter
Join Date: Feb 2005
Location: seattle, wa
Posts: 98
Received 0 Votes on 0 Posts
RE: It also appears that at one time a heavy load was connected to the left middle fuse as indicated by its discoloration.

Furd...it turns out this isn't discoloration. There are gray discs on all the other sockets, and each of those sockets have a brown/redish disc behind the gray.

This one just doesn't have a gray disc. Not sure why, nor what those gray discs do.
 
  #9  
Old 01-31-10, 10:53 AM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,597
Received 13 Votes on 11 Posts
O/T
Ray, there are no "aftermarket screw-in breakers" visible, only two standard plug fuses.
Pictures are worth a thousand words except when my tired old eyes view them. I swear those didn't look like empty sockets last night. The center contact looked like a button on the old time adapters to replace fuses. Geeze, thanks Furd for catching my obvious mistake. Apologies to Briholt.
 
  #10  
Old 01-31-10, 01:09 PM
B
Member
Thread Starter
Join Date: Feb 2005
Location: seattle, wa
Posts: 98
Received 0 Votes on 0 Posts
no apologies needed! Actually, it tells me I should take pictures at angle, and not straight on. Give the pic some perspectives for depth and what not....

Originally Posted by ray2047 View Post
O/T Pictures are worth a thousand words except when my tired old eyes view them. I swear those didn't look like empty sockets last night. The center contact looked like a button on the old time adapters to replace fuses. Geeze, thanks Furd for catching my obvious mistake. Apologies to Briholt.
 
  #11  
Old 01-31-10, 04:35 PM
F
Member
Join Date: Mar 2006
Location: NE Wis / Paris France{ In France for now }
Posts: 4,808
Received 0 Votes on 0 Posts
Furd did make a good suggest about replacing the old fuse panel to modern subpanel it will have alot more capitcty in there.

The way I can see the photo you already limited to 30 amp now that pretty much limted for this type of feeder you have.

Really I suggest that you can run new underground cable or conduit with THHN/THWN conductors cost wise you may want to check with big box store and the other thing you have to keep in your mind is bural depth you need keep them down at least 24 inches if direct burial otherwise with conduit it can be either 18 or 24 inches depending on your local code reqirement.

You will need one inch conduit for THWN/THHN conductors you will need #6 with 50 amp breaker and that is right on borderline max distance with this size.

let us know what is your options is

Merci,Marc
 
Reply
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: