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In-seat outlets and GFCI Testers

Posted: Mon Sep 13, 2021 6:19 pm
by 1337Delta764
As far as I know, in-seat outlets onboard aircraft are GFCI protected to prevent shocks from spilled beverages.

Theoretically, can someone bring onboard a GFCI tester and knock out the onboard outlets? I'd hate to be the unlucky one. Or does an aircraft GFCI circuit work differently from one in a building?

Re: In-seat outlets and GFCI Testers

Posted: Tue Sep 14, 2021 7:44 pm
by DL_Mech
Each seat should have its own power supply, so you would only take out your own seat row. I believe this is done to minimize wire size/ amount of wires with 120v.

Re: In-seat outlets and GFCI Testers

Posted: Wed Sep 15, 2021 8:13 pm
by kalvado
DL_Mech wrote:
Each seat should have its own power supply, so you would only take out your own seat row. I believe this is done to minimize wire size/ amount of wires with 120v.

What is the power system voltage generally? 28 V or something else?
I remember it used to be 400 Hz to reduce transformer size and weight, probably not a big deal anymore with all DC-DC converters today

Re: In-seat outlets and GFCI Testers

Posted: Wed Sep 15, 2021 8:24 pm
by DL_Mech
kalvado wrote:
DL_Mech wrote:
Each seat should have its own power supply, so you would only take out your own seat row. I believe this is done to minimize wire size/ amount of wires with 120v.

What is the power system voltage generally? 28 V or something else?
I remember it used to be 400 Hz to reduce transformer size and weight, probably not a big deal anymore with all DC-DC converters today


Traditional airplanes have 28v dc and 115v ac 400 hz (for smaller wire size). However, newer planes such as the A220 have mostly dc wiring running throughout with dc-ac conversion taking place inside the black boxes. I don’t know the reason for this new convention. Ideas?

Re: In-seat outlets and GFCI Testers

Posted: Wed Sep 15, 2021 9:13 pm
by kalvado
DL_Mech wrote:
kalvado wrote:
DL_Mech wrote:
Each seat should have its own power supply, so you would only take out your own seat row. I believe this is done to minimize wire size/ amount of wires with 120v.

What is the power system voltage generally? 28 V or something else?
I remember it used to be 400 Hz to reduce transformer size and weight, probably not a big deal anymore with all DC-DC converters today


Traditional airplanes have 28v dc and 115v ac 400 hz (for smaller wire size). However, newer planes such as the A220 have mostly dc wiring running throughout with dc-ac conversion taking place inside the black boxes. I don’t know the reason for this new convention. Ideas?

DC distribution should be a bit easier - definitely less crosstalk in electronics, simpler battery integration. With modern semiconductor converters making conversions small and light, motor-generators are forgotten as a nightmare and one can choose distribution without thinking about the cost of conversion.
On a very separate - but similar - note, I heard some ideas of DC-only residential grid. We'll see. Never thought I would say that, but changing architecture with a new jet type is easier than changing ancient residential standard.

Re: In-seat outlets and GFCI Testers

Posted: Thu Sep 16, 2021 8:17 am
by celestar345
For most outlets I have worked on if any fault occurs it will only take out the outlet in that particular seat - other outlets in the same row are not affected despite supplied from the same converter box. And the converter box takes power from one phase of the 3-phase 115V 400hz, the wiring rotates so the power loading across the cabin should be more evenly distributed on the three phases AC.

The outlets are pretty well built - although some do fail over time most of them takes a lot of abuse without fail. So if yours fail and you really need the outlet your next seat neighbor's should be working.