Clean or replace this box

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  #1  
Old 08-22-13, 07:03 AM
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Clean or replace this box

I am new to the forum, and a new home owner who would appreciate some solid advice.

I have just bought a 70 year old home that overall, is in great shape, but needs a few repairs.

The safety shutoff located above the hot water tank shows some corrosion on one of the 2 copper bars. There is also some old cloth wiring which leads to an additional on/off switch located in the bathroom for the hot water tank.

I am planning on changing the older cloth wiring for new wiring and removing the switch in the bathroom completely.

Should this box be replaced, or is a good cleaning of all the copper contacts enough to keep it in service for years to come.

There is a breaker in the main electric panel, this box is just the safety switch directly above the hot water heater.

Thank you,
 
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  #2  
Old 08-22-13, 08:47 AM
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Has your house's main panel been replaced with a breaker box? If so is this disconnect on a breaker and what size is the breaker?
 
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Old 08-22-13, 08:57 AM
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  #4  
Old 08-22-13, 09:12 AM
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Ray,

The main entry has been changed and the hot water tank is on a 40amp breaker.

All the wiring has been changed except for 3 loads, one being the hot water tank. Leaving cloth wire, without a ground to the disconnect at the tank. Local code (not sure if this is common across the land or not) requires a disconnect at the tank if the main entry is not within eye sight of the hot water heater.

Then one string of old cloth wire leads to the on off switch in the bathroom to shut the hot water heater off, and modem wire leads back to the disconnect.

My thought was to replace the cloth from the main panel 40amp breaker to the disconnect and completely do away with the on/off switch in the bathroom closet. I can go down to the basement and throw the main 40amp breaker or go to the tank and throw the disconnect if need be. Having a 70 year old cloth non grounded wire to yet another switch seems like risk with little gain and it should just be pulled out.
 
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Old 08-22-13, 09:48 AM
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Unless this is an unusually large water heater you only need #10 on a 30 amp breaker. The disconnect can be an unfused 30a (or 60a) A/C type disconnect. If the cable to the water heater is good and at least #10 I'd suggest just putting in a 30 amp breaker at the main panel and an unfused disconnect. You could also use a lockable breaker instead of a disconnect. No disconnect need if you can see the breaker box from the water heater and it is less than 50 feet away
 
  #6  
Old 08-22-13, 11:01 AM
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the hot water tank is on a 40amp breaker
Yet the fuses in the existing disconnect are just 20 amp. What is the wattage of the water heater? Today's typical electric water heaters are 4500 watts and the real old ones used to be lower wattage than that. The breaker size, wire size and rating on the disconnect are all determined by the wattage of the load, your water heater.
 
  #7  
Old 08-22-13, 01:03 PM
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Joe,
The fuses are 20amp per live line.
2 live lines to the heater.

The heater is actually small, 40 CDN gallons or about 50 US gallons. The Rheem web site leads me to believe it is 4500 watts.

If I change the tank at some point later on, to a standard 60 CDN gallon (72 US) the breaker size is good but the wiring a little small.
Given the current wire is cloth, I am considering changing it out now for modern wire, update the box and remove the old secondary switch upstairs.

The cost of boxes is far less in the US based on the link to Home Depot, an empty 60amp box here is about 60 dollars. Square D breakers are comparably priced.
 

Last edited by Kiton; 08-22-13 at 02:25 PM.
  #8  
Old 08-22-13, 01:38 PM
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The fuses are 20amp per live line.
2 live lines to the heater.
Yes, but it is not additive. It is just 20 amps.
The Rheem web site leads me to believe it is 4500 watts.
That is 20 amps which means the breaker and fuses should all have been 30 amps if wire size permits. The fact the fuses are 20 amps make me wonder if you really #8 wire which would be required for a 40 amp breaker. Almost wonder if it was on a 20 amp breaker at one time and someone changed out the breaker to 40 amps because the breaker kept tripping.

The cost of boxes is far less in the US based on the link to Home Depot, an empty 60amp box here is about 60 dollars. Square D breakfast are comparably priced.
As stated earlier you do not need a breaker box. An unfused air conditioner disconnect either 30a or 60a is all you need. Heres a $7 U.S. example: GE 60-Amp 240-Volt Non-Fuse Metallic AC Disconnect-TFN60RCP at The Home Depot even if Canada is double that only c$14. Or use what you have with 30 amp fuses.
 

Last edited by ray2047; 08-22-13 at 01:55 PM.
  #9  
Old 08-22-13, 02:44 PM
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Given the current wire is cloth, I am considering changing it out now for modern wire, update the box and remove the old secondary switch upstairs.
I think that's what I would do too. You'll still need a disconnect at the tank, but the one ray linked to is perfectly acceptable. I'd use 10-2 NM B cable and a 30 amp 2 pole breaker at the main panel. I doubt that even a 100 gallon water heater would be more than 4500 watts. 30 years ago there were a few water heaters with 5500 watt elements, but they would still operate on a 30 amp circuit. I haven't seen one of those in many years.
 
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Old 08-22-13, 03:30 PM
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If you still can't find a disconnect at an acceptable price when you buy the new breaker look for a lockout. You don't need a disconnect if the breaker has a lockout.
Example: Panduit Universal Circuit Breaker Lockout

[ATTACH=CONFIG]16649[/ATTACH]

Check local code to see if that is an option. Posts based on NEC not CEC.
 
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Last edited by ray2047; 08-22-13 at 03:48 PM.
  #11  
Old 08-22-13, 04:58 PM
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Thank you guys,

I have not purchased a pdf version of the Code, it is $130.00 a pop regardless of hard copy or PDF version.

The fuses seem to be one fuse per live line fed from these 2x 20amp breakers that are tie-barred or "pinned" (correct terminology ??)

After posting, I found this unit at Home Depot which should do the job:

Siemens | 60 Amp Outdoor Enclosed Non-fused Pullout Safety Switch, 1 Phase, 2 Wire, 240V Ac | Home Depot Canada

The big electrical supply house (which is a at least a 30 minute drive each way) has many options but all at several times the cost, so the $18 dollar option that is right around the corner is looking good.
 

Last edited by Kiton; 08-22-13 at 05:39 PM.
  #12  
Old 08-22-13, 07:05 PM
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The fuses seem to be one fuse per live line fed from these 2x 20amp breakers that are tie-barred or "pinned" (correct terminology ??)
That is a 20 amp breaker not a 40 amp breaker. I'd be willing to bet you only have #12. Both the breaker and cable must be replaced, 30 amp breaker and a 10-2 cable. Since this is Canada the cable must be 240 volt cable with red and black wires. You can not use 120v cable with black and white wires.

That non-fused pull out safety switch is exactly what you need.
 
  #13  
Old 08-22-13, 07:58 PM
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That is a 20 amp breaker not a 40 amp breaker. I'd be willing to bet you only have #12. Both the breaker and cable must be replaced, 30 amp breaker and a 10-2 cable. Since this is Canada the cable must be 240 volt cable with red and black wires. You can not use 120v cable with black and white wires.
You can also overkill and run 10-3g to the disconnect, then run flex conduit with red, black, and green THHN to the water heater.
 
  #14  
Old 08-22-13, 08:19 PM
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Technically, you have two 20 amp single pole breakers with a handle tie to make them function as a 2 pole. I prefer a 2 pole breaker without the handle tie. In your case, you need a 30 amp breaker anyway so what you need is a Square D QO230.
 
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Old 08-22-13, 08:25 PM
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You can also overkill and run 10-3g to the disconnect, then run flex conduit with red, black, and green THHN to the water heater.
Member is in canada. 10-2 made specifically for 240 volt is what is required. He could buy a premade whip to go from the disconnect to the water heater.
 
  #16  
Old 08-22-13, 09:02 PM
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Once again, thank you!

Showing my "rookieness", I though the 2 hot wires each on a 20 amp breaker was equivalent to a 40 amp breaker.

I was not aware of the need for 10-2 made for 240 volt, thank you Ray.
The $130 for a full copy of the code is looking more and more like a must buy.

The wire leading to the tank from the disconnect now is standard 12-2. The sticker on the tank says it was wired and installed in 2005 by a local plumbing contractor.

To give you an idea how some of the work was done, the 5 basement lights were wired as seen below, not a pig tail to be found, just stripped a small spot and wrapped around the connections. It feels like 2 different contractors have worked here over the years, one did quick hits and cut corners (I found a 14-3 wire leading to kitchen plugs just draped over the shelves below the kitchen counter for the entire length of the kitchen) and the other seems to have done very solid work.
 
  #17  
Old 08-22-13, 09:08 PM
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Joe,

So the 30 amp 2 pole will have 2 hots and a neutral pig tail that goes from the breaker to the neutral bus bar?

Originally Posted by CasualJoe
Technically, you have two 20 amp single pole breakers with a handle tie to make them function as a 2 pole. I prefer a 2 pole breaker without the handle tie. In your case, you need a 30 amp breaker anyway so what you need is a Square D QO230.
 

Last edited by Nashkat1; 08-22-13 at 10:00 PM. Reason: Format quote
  #18  
Old 08-22-13, 09:57 PM
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Showing my "rookieness", I though the 2 hot wires each on a 20 amp breaker was equivalent to a 40 amp breaker.

I was not aware of the need for 10-2 made for 240 volt, thank you Ray.
The $130 for a full copy of the code is looking more and more like a must buy.
A set of codes - any codes - is only useful to someone who is trained and experienced, over several years and many jobs, in using - interpreting - that code. I would suggest that you spend less than 10% of that amount and buy a copy of Wiring Simplified instead.

Wiring Simplified is authoritative, continually updated, and written to be understood by a layman. The only caveat is that you'll need to be aware of the differences between the NEC, which it's based on, and the CEC. One is the requirement to use only cable with two conductors marked as carrying ungrounded potential (two "hot wires") for a 240V circuit, as already mentioned. Another is that, under the CEC, only 20A devices may be installed on a 20A circuit. There are others, I'm sure, but the overall information should be nearly identical.

The wire leading to the tank from the disconnect now is standard 12-2. The sticker on the tank says it was wired and installed in 2005 by a local plumbing contractor.
4500W/240V = 18.75A. Everything may be OK as it is, except that the two single 20A breakers should be replaced with one 2-pole 20A 240V breaker.

So the 30 amp 2 pole will have 2 hots and a neutral pig tail that goes from the breaker to the neutral bus bar?
No. Only GFCI and AFCI circuit breakers have neutral wires built into them to be connected to the neutral bus. There is no need for either GFCI or AFCI protection on this circuit. In addition, this 240V single-phase circuit is wired with two hots and one ground. There is no neutral in the wiring to connect to the breaker, and through it to the bus.
 
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Old 08-22-13, 09:58 PM
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So the 30 amp 2 pole will have 2 hots and a neutral pig tail that goes from the breaker to the neutral bus bar?
No. Neutral has nothing to do with a breaker in most cases (and exceptions aren't applicable here). This is a 240 supply. There is no neutral on a 240 volt supply. That is why you use a 2-conductor (+ground) cable, 10-2.
 
  #20  
Old 08-23-13, 12:47 AM
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4500W/240V = 18.75A. Everything may be OK as it is, except that the two single 20A breakers should be replaced with one 2-pole 20A 240V breaker.
I have no idea if the CEC is the same but the NEC considers a storage tank water heater to be a continuous load. As such the branch circuit is required to be designed to 125% of the load, in this case 1.25 times 18.75 or 23.44 amperes. That requires no less than number 10 copper conductors and a 25 or 30 ampere circuit breaker.
 
  #21  
Old 08-23-13, 07:14 AM
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Thank you very much, I think I am ready to start this job.

Nash, I have ordered the Wiring Simplified book from Amazon, Home depot does not sell it here and there does not seem to be a legal PDF version available for purchase, only a Kindle version.

There is no ground on this line, between the cloth (but copper, not aluminum) wire and no ground, I am looking forward to getting this one completed.

Next up once this is completed is a 30amp breaker using old aluminum wire that has 21 load centers on the single breaker!
 

Last edited by Kiton; 08-23-13 at 07:43 AM.
  #22  
Old 08-23-13, 07:55 AM
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Member is in canada. 10-2 made specifically for 240 volt is what is required. He could buy a premade whip to go from the disconnect to the water heater.
Exactly right, it's easy to forget that there are differences between the NEC and CEC, but this is one I do remember after ray's reminder.

The wire leading to the tank from the disconnect now is standard 12-2. The sticker on the tank says it was wired and installed in 2005 by a local plumbing contractor.
I suspect the plumber just reconnected to the existing wiring. Most typical plumbers are not interested in nor do they have the materials on their trucks to install a complete new proper circuit. The wiring between the disconnect and the tank could be a pre-made whip as ray suggested, or it could be flexible metal conduit field installed with the #10 conductors.
 
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Old 08-23-13, 07:59 AM
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4500W/240V = 18.75A. Everything may be OK as it is, except that the two single 20A breakers should be replaced with one 2-pole 20A 240V breaker.
I have no idea if the CEC is the same but the NEC considers a storage tank water heater to be a continuous load. As such the branch circuit is required to be designed to 125% of the load, in this case 1.25 times 18.75 or 23.44 amperes. That requires no less than number 10 copper conductors and a 25 or 30 ampere circuit breaker.
This is another issue that Furd has hit right on according to the NEC. I have no idea if the CEC is the same, but I suspect it is very similar. I'd definitely use #10 copper conductors and a 30A 2P breaker.
 
  #24  
Old 08-23-13, 08:30 AM
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I am not sure what Canadian code is says on the load of the tank being 1x, 1.5x etc

I had hired an electrician when I first took possession of the home, he was here 2 hours and wired 2 dishwashers and a clothes dryer, the bill was $1100.00 (15 percent of that was goods and services taxes), and I bought the wire on top of that.

The only upside was I peppered him with as many question about code as I could during his visit. He only mentioned the 80% maximum load rule while speaking about the tank when I mentioned I wanted to remove the secondary on off on switch located in the bathroom.
 
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Old 08-23-13, 09:07 AM
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The only upside was I peppered him with as many question about code as I could during his visit. He only mentioned the 80% maximum load rule while speaking about the tank when I mentioned I wanted to remove the secondary on off on switch located in the bathroom.
Even using the 80% rule, you'd still need #10 conductors and a 30 amp breaker.
 
  #26  
Old 08-23-13, 06:34 PM
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Eighty percent is the reciprocal of 125%. Either upsize (multiply by 1.25) the connected load or downsize (multiply by 0.8) the total circuit Ampacity and you get the same results.
 
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Old 08-23-13, 08:55 PM
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the NEC considers a storage tank water heater to be a continuous load.
Well, son of a gun, so it does - at least some of them:
422.13 Storage-Type Water Heaters. A fixed storage-type water heater that has a capacity of 450 L (120 gal) or less shall be considered a continuous load for the purposes of sizing branch circuits.
OK. You need a 30A 240V circuit with 10AWG conductors for that water heater. You can just replace the fuses in the service disconnect but you'll need a new breaker in the panel.
 
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