August 17, 2017 – Will you get stumped by T-slot (5-20R) receptacles? Tackle this month’s Code Conundrum… if you dare!

Question 1
The ampacity of the supply conductors from a small turbine system shall not be less than ____ of the generator’s maximum current rating.

a) 125%
b) 135%
c) 250%
d) 300%

Question 2
The ampacity of the feeder supplying a total of 60 kW of heating equipment in an apartment building, from a 208V, 3-phase switchboard is:

a) 132A
b) 168A
c) 125A
d) 156A

Question 3
T-slot (5-20R) receptacles installed at a commercial building and exposed to the weather are required to be provided with wet location cover plates, regardless of whether a plug is inserted into the receptacle or marked “Extra Duty”.

a) True
b) False

ANSWERS to these questions in September’s Electrical Business Magazine. MEANTIME, here are the answers to the June 2017 Code Conundrum!

Answer 1
Which of the wiring methods listed below is not allowed in a Zone 1 area?

c) Threaded rigid metal conduit with approved glands. Rule 18-102(1).

Answer 2
At least one duplex receptacle must be in a residential porch.

a) True. Rule 26-712(b).

Answer 3
A wall switch located at the head of the stairs shall control all the luminaires located in an unfinished basement.

b) False. Rule 30-506(2).

The Code Conundrum is compiled by Ray Yousef, a code engineer with Ontario’s Electrical Safety Authority.

N.B. Always consult your AHJ for more specific interpretations.

* This article also appears in the July-August 2017 edition of Electrical Business Magazine. Check out our ARCHIVE page for back issues.