Upgrade 240 VAC service

[mnje350]

Hi All,

I am new to the forum so I appreciate all the help in advance.

I am considering replacing my radiant cooktop with a new induction type. Currently I have a two pole 25 amp breaker connected to E732071 4 CDR 6 AWG AL Alumaflex cable to supply power to the existing appliance. The connection point is about 60 feet from the electrical panel.

My question. Will the existing wiring handle 50 amp service which the new cooktop requires. If so, will all I need to do is switch out the breakers?

Something is telling me that the existing wiring will also have to be replaced. The new cooktop is 10.5 KW @ 240 VAC. The existing cooktop is 8.1 at 240.

Thanks again for the help.

 

[James-W]

What size wiring do you currently have going to to the cooktop?

 

[Charles (in GA)]

What size wiring do you currently have going to to the cooktop?

"6 AWG AL" he says.

No, this is not suitable for 50 amp, you will need #4 in AL or #6 in Cu for 50 amps. Possibly more if you adhered to the 80% rule.

Charles

 

[mnje350]

"6 AWG AL" he says.

No, this is not suitable for 50 amp, you will need #4 in AL or #6 in Cu for 50 amps. Possibly more if you adhered to the 80% rule.

Charles

This is what I was afraid of. Now I just need to get a quote on the proper wiring. I hope it is not too expensive.

 

[Zeke]

If you were going to do the new hook up and replace the breaker, can you not run some wire?

 

[mnje350]

I probably could because the house is on a crawl space. It's getting the cable to the panel without ripping the wall apart that scares me. That and drilling another hole in the sill plate without tearing into some other wiring. Plus, I know my panel is maxed out, in terms of available slots for breakers. In this case, after running new cable I would simply swap out the 25 A two pole for a 50 a 2 pole. But then I am wondering if I would be overloading the panel???

I have 200 amp service but I don't know how to calculate the maximum amperage allowed for all of the branch breakers. Any ideas on that?

Everything else I am fine with.

 

[Falcon67]

200A service doesn't mean you're limited to ten 20A breakers. The breaker is sized to protect the wire on that run. You could have 30 breakers in a panel if thats what it takes to break up the circuits for maintenance or code requirements. Our 200A panel is a 30/40 - it's "full" but with some re-arranging I could change out 10 singles to doubles and still be within mfg specs. Depends on your panel. There should be a sticker on it that clearly says what your limit is on breakers.

 

[pattenp]

The simple answer for load calculation is the total sum of amps of everything that you can anticipate being on at the same time. There are also adjustments for needed capacity if the loads are continuous vs. non-continuous, (100% for non-continuous loads, 125% for continuous loads). It's not the sum of the amp rating of all the breakers in the panel.

Here's the more complex answer.... http://ask-the-electrician.com/residential-electrical-load-calculation.html




*

 

[mnje350]

Thanks everybody for the help. You guys are awesome.

Most, if not all, of my loads are non-continuous. Two heat pumps with Aux heat, water heater, Range, cook top, dryer, microwave, then the usual branch circuits for lights and convienence outlets for a 3600 sq. ft house. I know, I know, the builder cheaped out and should have put in 400 amp service for a house this size but that ship has long since sailed. If I did in fact add up all of the ratings on the breakers in the panel it would be way more than 200 amps. I just did not know where the upper limit was.

Now I should be able to figure out if I have an expensive upgrade or a really expensive upgrade. If the latter, I may opt for an LP gas cooktop. Already have the tank for the fireplace so that could be an option if the panel is maxed out. I would just rather go with one of these induction cooktops if at all possible.

 

[wyliesdiesels]

Ummm everything u listed IS considered a continous load. Well except for the microwave, unless of course youre ghetto and cook everything in the microwave

U have an all electric house(well except for the fireplace) and a large one at that. I would do a load calc to make sure youre okay...Mad switch some of those appliances over to LPG!

 

[Charles (in GA)]

Code says any heating equipment, be it cooking, water, or heat for room or building, is continuous. Anything else that is reasonable expected to operate for more than three hours non-stop is also continuous, which in many cases means lighting.

Charles

 

[mnje350]

Hmmm,

This is the knowledge that I lack. Sounds like I need a panel inspection before any upgrades are done. I guess I am looking at a gas cooktop. Well at least that will lighten the load on the service panel.

Thanks again guys.

 

[Speedy Petey]

Code says any heating equipment, be it cooking, water, or heat for room or building, is continuous. Anything else that is reasonable expected to operate for more than three hours non-stop is also continuous, which in many cases means lighting.

Charles

Please show me where it says cooking equipment is considered a continuous load.
It's quite to the contrary, household cooking appliances are held to an even less stringent demand load calculation.
This 10kW cooking appliance is under 12kW, so all it needs is a 40A breaker according to the NEC, if the instructions say different then that's what we follow.
Also, since when is #6AL SER not good for 50A??? If it were NM cable then it is limited to 40A, but #6AL NM Is pretty rare to see.

 

[Speedy Petey]

Ummm everything u listed IS considered a continous load. Well except for the microwave, unless of course youre ghetto and cook everything in the microwave

I have to disagree here. Most of that is definitely not considered a continuous load in the eyes of the code. In fact, much of everything in a home is not, other than the specific things called out in the code, like fixed electric heat and water heaters.

We have to remember the actual wording in the definition of continuous load.

Continuous Load.
A load where the maximum current is expected to continue for 3 hours or more.

 

[mnje350]

I have to disagree here. Most of that is definitely not considered a continuous load in the eyes of the code. In fact, much of everything in a home is not, other than the specific things called out in the code, like fixed electric heat and water heaters.

We have to remember the actual wording in the definition of continuous load.

Hmmm,

This helps a bit. About the only appliance that I can think of that would use its max draw for 3 or more hours would be a self cleaning oven. God help me if my HVAC were to do that. So maybe my panel is not so bad afterall.

 

[pattenp]

Also, since when is #6AL SER not good for 50A???

When it's installed within thermal insulation.

 

[Zeke]

I like cooking with gas but the new induction cooktops are great. Don't change your plan. But, you have to buy new cookware with the induction symbol.

 

[mnje350]

I have an electrician coming to look but once I properly identified the cable I think it will be OK. Had to crawl around in the crawl space to read the whole jacket. SE type SER 4 CDR 6 AWG AL XHHW-2. With the 90 Degree C rating this should be good for 50 A. The max load the appliance will draw is 45 A.

 

[wyliesdiesels]

I have an electrician coming to look but once I properly identified the cable I think it will be OK. Had to crawl around in the crawl space to read the whole jacket. SE type SER 4 CDR 6 AWG AL XHHW-2. With the 90 Degree C rating this should be good for 50 A. The max load the appliance will draw is 45 A.

First of all, 90* c is for derating purposes only. So SER ampacity starts at 75* c rating. Then if its buried in insulation more than 10% of the run(IIRCC) then its limited to 60* c ampacity...so were talking 50a and 40a....