A Tankless Water Manufacture claims that their 28.8 KW Intermittent electric device can be installed on one?s "home if the home has a 200 amp electrical service panel (or larger) you likely have enough service to power their unit"? I don?t see that this will work if the home has electric heat! What should my load calculation look like? :-?
Load Calculation - Tankless Water Heater
- Thread starter rtcotton
- Start date
- Status
Sierrasparky
Senior Member
- Location
- USA
- Occupation
- Electrician ,contractor
Calculate as usual.
Is this a full time residence or a vacation home. just curious.
Is this a full time residence or a vacation home. just curious.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
RT, welcome to the forum! 
The tankless water-heater people are generally clueless about the effects their products have on electrical systems. I haven't installed more of them than I have installed because I was candid about it with the potential customer.
One such customer had a single 200a service and a panel that supplied, among other things, a 100a feeder to a detached 4-car garage with an apartment above it, and a 100a feeder to a basement apartment with a separate kicthen.
I explained the risk of simply adding the water heater without doing a service upgrade now, the cost of doing it with an upgrade now, and the cost of doing it later, if needed, on a separate call. They decided to skip the install.
The people who sold them the heater weren't very happy with me, but I still maintain that I did the proper and responsible thing, and I'd do it again. If their main breaker tripped, and I hadn't warned them about it, they'd blame me.
Just remember this: It's a tankless job.
The tankless water-heater people are generally clueless about the effects their products have on electrical systems. I haven't installed more of them than I have installed because I was candid about it with the potential customer.
One such customer had a single 200a service and a panel that supplied, among other things, a 100a feeder to a detached 4-car garage with an apartment above it, and a 100a feeder to a basement apartment with a separate kicthen.
I explained the risk of simply adding the water heater without doing a service upgrade now, the cost of doing it with an upgrade now, and the cost of doing it later, if needed, on a separate call. They decided to skip the install.
The people who sold them the heater weren't very happy with me, but I still maintain that I did the proper and responsible thing, and I'd do it again. If their main breaker tripped, and I hadn't warned them about it, they'd blame me.
Just remember this: It's a tankless job.
Sierrasparky
Senior Member
- Location
- USA
- Occupation
- Electrician ,contractor
Yes you need to look at how the customer will use this type of product also. Hence the reason I asked is it a vacation home. When I see vacation home I see this scenario. In the cold of winter the guest arrives. They turn on all the heaters because the house is only 50 deg. Then they may have had long drive so they take a shower before dinner. A whole housefull of guests this could be a potential heavy load on the panel. I've seen plenty of burned up buss bars in the dead of winter.
A normal household should not see these spikes in demand as all the electric heaters would not be on at once and for a long period of time.
A normal household should not see these spikes in demand as all the electric heaters would not be on at once and for a long period of time.
SG-1
Senior Member
- Location
- Ware Shoals, South Carolina
Another consideration is if the HO has a backup generator. This stopped me from installing a tankless for my own use.
IMO, Per 220.51 and 220.53 the tankless and the electric heat should be calculated at 100%
mivey
Senior Member
Then it would look like a strobe light.:grin:
- Status