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# Limits of a 20 Amp Circuit

## Limits of a 20 Amp Circuit

#1
06-02-23, 08:40 PM
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Limits of a 20 Amp Circuit

We have a property soon to be occupied after a so-so remodel. Checking it out, I noticed there are 5 outlets on the kitchen counter. (Protected by one GFCI) So I got curious and found out they were all on one 20 amp breaker. Looking further that 20 amp breaker also supplies 2 outlets in the master bathroom and 3 outlets in the dining room.

Would the norm be 3 maybe 4 separate circuits to carry all this?

Meanwhile I'm trying to understand the limits of a 20 amp circuit. 1st I understand that's 2,400 watts max. Secondly, however that breakers don't really trip until they hit about 130% of that value? Is that accurate? (That would be 3,120 Watts) Or something like that....? Does a 20 amp breaker trip at exactly 20 amps?

Going forward, We're trying to consider all the factors involved. And if the worst thing is simply nuisance tripping? Since we may or may not rectify all this prior to the place being occupied.

#2
06-02-23, 08:57 PM
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By code.... there should be 2) 20A dedicated "counter only" receptacle circuits.
You can put several counter receptacles on each circuit.

One 20A circuit is going to be limited if you use several appliances at once.

CasualJoe voted this post useful.
#3
06-03-23, 04:51 AM
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Dining room is permitted on the kitchen counter receptacles.
Bathroom is supposed to be on its own dedicated 20 amp circuit.
By code the receptacle you describe should be on three 20 amp circuits.

#4
06-03-23, 04:58 AM
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Does a 20 amp breaker trip at exactly 20 amps
No. They are inverse time circuit breakers meaning that the more you go over their rating the faster they will trip. A breaker loaded to 30 amps could take 15-20 mins to trip while a breaker loaded to 40 amps will take about 1 min.

Really, PJmax is correct. The unit should have at least two small appliance circuits that should only serve the kitchen. These small appliance circuits are allowed to serve the dining room and other kitchen receptacles.

#5
06-03-23, 05:52 AM
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Thank you for all the replies.

From this point on, barring separating the circuits to 3 breakers, would nuisance tripping be the only real drawback? (FYI the house was built in 1961 and the panel was recently changed out.)

#6
06-03-23, 07:24 AM
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From what I can tell it is grandfathered. All those outlets can stay as is for now. They won't cause nuisance ground fault tripping but you will get nuisance overload tripping of the panel breaker.

At your leisure you can string additional circuits with an additional one for the bathroom, separate circuits for lights, dishwasher, etc., and also to get more different circuits for the dining room and kitchen receptacles.

Note: If there is any 14 or thinner gauge wiring on that circuit then the breaker must be immediately downgraded to 15 amps.

#7
06-03-23, 09:58 AM
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(FYI the house was built in 1961
A house built in 1961 could have Greenfield (FMC) as the wiring method. Perhaps you may be able to just pull in some new circuits.

​​​​​​​and the panel was recently changed out
FYI 2020 NEC requires a surge protector to be installed in/at the panel when it is replaced.

As long as the wires are the proper size for the breakers installed and all the connections and devices are in good condition it will likely be OK. However, it is not a good idea to test a wiring system by overloading the circuits.

#8
06-03-23, 06:15 PM
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Thanks guys. The panel, when I said recently changed out....I think the inspection sticker reads 2019.

There's no FMC in the house. What we do have...it's this NM cable which has this really thin like #16 or #18 bare ground wire.

Is there a common trade name or nick name for this type of cable?

#9
06-03-23, 08:15 PM
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Not that I know of. It is just an early version of NM cable. Of course, Romex is a brand name like Kleenex.

#10
06-07-23, 08:43 PM
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When I opened the 20 amp outlet boxes, some contained a separate 15 amp switch/circuit for nearby lights. What I noticed is that the 12 gauge grounds were twisted together, and the 14 gauge grounds were also twisted together. They were not however connected to each other into one wire nut.

Is this practice normal, useful; or relevant in some way?

#11
06-08-23, 05:14 AM
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All grounds from all circuits, no matter the amp rating, should be connected in a junction box.

#12
06-08-23, 05:54 AM
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It's grandfathered but today just twisting is not sufficient to bond the equipment grounding conductors. Use a (bare or green) pigtail to join them if the two (you said #12 and #14 respectively) ground bundles won't reach or won't all fit in one wire nut.

Neutrals must be kept separate to the extent that each incoming (feeding) cable's neutral must serve all and only those neutrals in continuing cable(s) served by the matching incoming hot conductor(s)..

Last edited by AllanJ; 06-08-23 at 06:08 AM.