electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
- Occupation
- Electrician
Interesting. I have never seen such information marked on a data plate. I have also never "supplied power separately" to an indoor unit.
Multi head ductless unit; nameplate marking 440.4(B)
- Thread starter tortuga
- Start date
Ahh good find thank you, so they are doing some like the regular old ducted systems.
As I said before they often don't have the unit, or a different one shows up than on the cut sheet but now I'll be asking how many 'heads', and if it has these ducted 'ceiling cassettes' instead of wall head units.
In my case the unit on the approved plan set was discontinued by the time they were ready, so a completely different unit was used.
And I still like to follow along and see how they got their numbers.
mtnelect
HVAC & Electrical Contractor
- Location
- Southern California
- Occupation
- Contractor, C10 & C20 - Semi Retired
I am a Daikin dealer and have gone through many Inservice Training sessions at my distributor and have installed many Daikin Dustless Systems for several years. As required by UL (Underwriter Laboratory) they have been tested and certified, see attachment. Electricians only need to follow the label on the outside unit.
I don't install conventual HVAC (Heating Ventilation Air Conditioning) split systems anymore, because they are a waste of energy. Ductless systems are taking over conventual split systems.
So, maybe Mike Holt can add some training to his code training seminars to help Electricians identify the differences between HVAC systems to prevent miss wiring to them.
I don't install conventual HVAC (Heating Ventilation Air Conditioning) split systems anymore, because they are a waste of energy. Ductless systems are taking over conventual split systems.
So, maybe Mike Holt can add some training to his code training seminars to help Electricians identify the differences between HVAC systems to prevent miss wiring to them.
winnie
Senior Member
- Location
- Springfield, MA, USA
- Occupation
- Electric motor research
1) IMHO the label on the outdoor unit should include the power requirements of the interior units, and the electrician should be able to simply follow the MCA and MOCPD requirements on the label.
2) It seems that in at least some instances, companies are not labeling things in a fashion that permits the above.
2) It seems that in at least some instances, companies are not labeling things in a fashion that permits the above.
Thats very interesting thanks Michael so they have phased out UL 1995 in favor of a what appears to be harmonized UL/CSA/IEC 60335 I'd imagine MCA would still be calculated the same way.
UL 1995 gave the manufacturer 3 differnt was to calculate MCA, as follows, presumably they used to use b) but the unit I have in post 6 namplate shows its UL 60335 not UL 1995.
mtnelect
HVAC & Electrical Contractor
- Location
- Southern California
- Occupation
- Contractor, C10 & C20 - Semi Retired
The new flammable refrigerants, that have been introduced to help the manufacturers meet the higher federal EPA (Environmental Protection Agency) standards, require the UL to change their testing standards to include international manufacturers.
mtnelect
HVAC & Electrical Contractor
- Location
- Southern California
- Occupation
- Contractor, C10 & C20 - Semi Retired
With Daikin's Matrix, you can see all the inside units that match with all the outside units. This information is for the installers only, not the Electrician. All the Electricians have to do, is follow the label on the outside unit.
The Daikin Installation Manual shows that no Electrician is needed for the inside units and the MPOD (Maximum Protective Overcurrent Device) and the MCA (Minimum Circuit Ampacity) will never equal your independent calculations since it is dependent on UL 60335 2 40 requirements.
hbiss
EC, New York NEC: 2017
- Location
- Little Falls, New York NEC: 2017
- Occupation
- EC
I was going to mention that before but I was unsure of how the manufacturers come up with their numbers.
-Hal
wwhitney
Senior Member
- Location
- Berkeley, CA
- Occupation
- Retired
Your post does not address the question of whether the outdoor unit nameplate includes the maximum interior load that "matches" and may be supplied from the outdoor unit.
Cheers, Wayne
In UL 60335 They describe how to determine MCA starting on page 176, here are the relevant pages from a 2022 version;
wwhitney
Senior Member
- Location
- Berkeley, CA
- Occupation
- Retired
hmspe
Senior Member
- Location
- Temple, TX
- Occupation
- PE
MCA is not helpful for determining the load to be used in a panel schedule. The data in data sheets for mini-splits seems to be inconsistent. The data sheet in post 42 lists Rated Power Consumption and Current Input. The values are not the same and the data sheet does not say what the numbers provided include or what they would be used for. For an electrician adding a unit where no detailed load calculation is required I have no problem with the "follow the MCA" advice above. For engineers doing panel schedules and calculations that have to go through plan review that's not the best approach. MCA by definition is higher than running load so it artificially increases the panel's total load.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
I have never seen an indoor unit for minisplit that would draw that kind of current, even if that it the sum of 8 indoor units it is kind of high.
electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
- Occupation
- Electrician
So does that settle it? Sounds like the outdoor MCA reflects the max number of indoor units?
Yeah these are very different units that I have been seeing hence the thread. Not the typical unit you see up high on the wall inside a room.
The HVAC person is removes a conventional ducted furnace, but keeps short sections of duct work in say a attic, and installs these blower 'head' units in the attic. They attach to the existing last 6' or so of duct work, so one unit can supply 3 small bedrooms as a 'zone' without having to find wall space in each bedroom for a head unit.
wwhitney
Senior Member
- Location
- Berkeley, CA
- Occupation
- Retired
I think so, for units listed to IEC 60335-2-40, assuming the excerpt above is accurate. I didn't find a way to read the standard free online from the source itself.
Cheers, Wayne
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
I haven't seen that yet on the conventional "mini split" system.
I have connected up larger VRF system before in a school building, conversion not new building. Most rooms had "cassettes" that lay in drop ceiling, but they did have a couple areas that had a fan coil unit that replaced old air handlers and reused the ductwork for those areas as well as larger self contained air handling units for the GYM and shop areas. But all the air handling units in that application were on a different circuit than the compressor unit. Several air handling units were all on same branch circuit, Those cassette units in drop ceiling in particular were only rated like 50 watts or so @ 208-240 volts. The compressors units were all three compressors in one unit with MOCP of the unit varying between 60 and 80 amps (three phase) One thing about these was you could heat one room and cool another (with heat removed from the first room) Not sure if many minisplits are capable of that or not. I'm sure it can be done just don't know if they add that feature to very many of them. The VRF system ran three refrigerant lines between compressor unit and "mode change units" and then two lines to each individual air handler from the mode change unit to be able to do this. The so called mode change unit would likely need to be built into the compressor unit of the typical multi outlet system I would think or have a separate mode change unit somewhere in the system.
Eddie702
Licensed Electrician
- Location
- Western Massachusetts
- Occupation
- Electrician
I agree with @hbiss
Even though it is a split system the outdoor unit is NG without the indoor and vise versa. It is not a typical split with a condenser and AHU. Its more like a package unit. The indoor units are specific to the condenser. The MFG should be marking the condenser for the total MCA and MOCP. If they are not that is just plain wrong.
Even though it is a split system the outdoor unit is NG without the indoor and vise versa. It is not a typical split with a condenser and AHU. Its more like a package unit. The indoor units are specific to the condenser. The MFG should be marking the condenser for the total MCA and MOCP. If they are not that is just plain wrong.
mtnelect
HVAC & Electrical Contractor
- Location
- Southern California
- Occupation
- Contractor, C10 & C20 - Semi Retired
The installing Electrician should have a conversation with the installer, before starting a job and read the Installation Manual before wiring. The attachment below, shows a commercial Daikin unit, that does require two dedicated circuits used sometimes in larger homes.
