15.09.20

All things racks

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Planning is crucial to building a neat rack. Image: Visualization

There is a lot to be considered when building racks – after all, it is the heart of a home system. Amy Wallington highlights some of the best tips and tricks to building a neat and functional rack.

The home automation panel is the central point within a smart home. It houses all the technology to control various tasks and operations in everyday home life, including lighting, heating and cooling, security, access, audio/video, and more. Therefore, it is crucial the rack is built properly for the equipment to function correctly. It’s also good to ensure the rack is neat and tidy, not just for aesthetic reasons, but it also makes it easier to know what’s what.

Building racks and panels can be a lengthy and complicated process and it’s sometimes hard to know where to start. With so many solutions available on the market, it is very important to ensure a good plan is put in place to tie all the technology together.

Fail to plan, plan to fail
Most people you speak to will tell you that planning a rack build is the most important step. Without a clear plan, time and money is wasted and you end up with a messy end result that does not function properly. 

Nick Pidgeon, managing director and owner of Visualization Limited, advises: “Planning is most important. The overall project design should have already been completed but this then naturally leads onto rack elevations, deciding on the best connection method for rack to site cabling, and breaking down the build process and timescales. Lack of planning leads to building on the fly, which often results in last minute changes, delays and knock on to programming and commissioning, which all have underlying costs that will come from the integrator’s budget.”

The planning process requires thinking about the project as a whole and what is needed. “You start with your rack specification,” says Pidgeon. “This will require an understanding of the rack location in the property and also the volume of RU (rack unit) space required. What restrictions are there? Space including height, width and depth, ambient temperature, the connection method – is there adequate space for a headend panel? This should all help to select the correct rack or racks to meet the requirements.”

Something else to consider during the planning process is weight distribution and the order that things will go in. Keith Jones, partner at designflow, explains: “As the old saying goes, if you fail to plan, you plan to fail. In terms of the design, it’s important to put hot and heavy items at the bottom which helps with thermal management and means the rack is stable and is not top heavy and likely to fall over. 

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The finished product from Majik House

“It is also important to consider the practicality of wiring and keeping separation between mains distribution and networking cables and equipment. We tend to group things from the bottom by audio (the bulk of the amplifiers), AVR (if included), video, mains distribution (except UPS which must go at the bottom due to weight), CCTV, control, and finally networking at the top.”

Kris Winder, a programmer for Majik House, suggests that power requirements and heat output are key considerations too. “You will need to calculate how much power the rack will need so you can provide this information to the electrician. You can also work out your heat output to provide to the HVAC company so they can supply the correct amount of cooling. This leads to a plan of where to place each piece of equipment within the rack for cable routing. Each cable used in the rack needs to be accounted for from the wiring schedule and labelled and documented.”

Wiring schedules
This leads us to the wiring schedule, a document that details every single cable that goes into the rack to keep track of everything. 

Zach Meek, home automation engineer, Zmart Hohm, goes through this process. “Following the initial project brief, it is important to liaise with every engineering trade on site, such as renewable/heating/security/AV engineers, to generate a wiring schedule. This document details every cable being installed with a unique number which also references the connection point within the top DIN rail. It also shows which cable is used, the voltage used, and the location it needs to be wired to.”

Winder adds: “The first thing I do when building a rack is to make a list of the equipment then draw out the plan and cross off each item I have so I don’t forget anything and remember to allow for ventilation space. Without having a plan for your rack, you end up running into problems very fast, from running out of room in the rack, equipment overheating, forgetting cables, and more, all leading to a poor install and system, and an unhappy client.”

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designflow can assist integrators with the planning process of a rack build

Build stage
In Meek’s work, his process starts with setting back the top DIN rail so that it is not seen with the panel cover on. He explains: “This would be the only connection point used for engineering trades on site. 

“Using the Weidmuller connectors, you can then terminate one cat cable or twin and earth within the space of 5/10mm on the DIN rail. This would normally allow adequate space to situate all the dwelling’s inputs/outputs across one DIN rail. The following DIN rails would then hold the various control modules of choice. Finally, all power supplies and circuit breakers are installed.”

Pidgeon believes that before the build process starts, integrators should begin with a system overview to allow familiarisation of the project and ask any questions that need clarification. It also allows the integrator to identify all cable types, lengths and connectors needed to ensure all ordering is complete and allocate a build time for each step before the build commences. 

“As the old saying goes, if you fail to plan, you plan to fail.”

“The first step is cable preparation,” suggests Pidgeon. “All cables should be cut, numbered, and terminated at one end with additional connectors allocated. We aim to custom make as many of the cables as possible to reduce the need to lose excess length, with the exception of HDMIs, resulting in a neater build.

“Second is the loading process, where simultaneously to the cable preparation, all the equipment will be serial number tracked against the project and the rack loaded, including cable management and any custom termination panels.”

Once the rack is loaded, everything needs to be connected in the lacing process. Pidgeon continues: “This is where the skill and experience shines through and is ultimately the key to a neat rack. The best advice I can give here is to work from the busiest pieces of equipment.”

Meek talks us through an example of his process: “Boot lacing every termination is important to minimise short circuit faults – it is easy to lose a few cores using Tri-Rated cable. I use 1.5mm Tri-Rated cable in as many connections as possible to maintain regularity which I believe is aesthetically beneficial. To maintain cable segregation of Band I and Band II circuits within the panel, as a rule of thumb, I run all LV circuits to the left trunking and all ELV on the right. 

“Following BS 7671, I provide fused down terminals for all extraction fans within the panel itself, illuminating the requirement for fused spurs before every fan isolator within the building. All inputs and outputs are manually labelled on the DIN rail. Only the first connection of each module is then labelled for a quick reference point when fault finding or testing. This may be controversial to not mark every core manually, but rest assured all connections are digitally marked within the Loxone configuration software.”

Finally, all racks should then undergo a thorough inspection prior to signoff to ensure everything is built correctly. “At times, cables with similar identification can be routed incorrectly or individual interpretation may cause a discrepancy,” admits Pidgeon. 

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Lacing keeps the cables neat and tidy and easy to trace. Image: Zmart Hohm

Top tips
If space allowed, we could go into a lot more technical detail on building a rack. However, there are some crucial elements that cannot be missed.

Pidgeon’s main piece of advice is to consider having sufficient space within the rack. “Don’t go with the minimum size based on the price. The extra space will provide the room required for cable management and result in both a neater and more efficient build.”

Another reason to consider space and size is for future upgrades. Jones says: “It is always important to leave room for expansion. Think of it like this – a customer is for life, not just for Christmas. You are going to want the opportunity in the future to upgrade their equipment. Imagine how frustrating it would be if they wanted to add a 16x16 video matrix of 6U to a rack that currently has a 4x4 1U matrix and you only have 2U to spare. Most integrators will make the sale anyway and then find a way to make it fit which will either be a messy bolt-on or a complete rack rebuild, neither of which are ideal.”

Jones also suggests something that will keep the rack looking neat and tidy. “We like to use network switches with rear facing ports where possible as this gives a neater appearance and makes for simpler cable dressing. If your switches have front facing ports, always allow for a brush panel above or below so the cables can come neatly through this from inside the rack.

“We also always design with custom rack shelves for equipment that is not rack mounted. These come with faceplates that are cut to fit the equipment so it can poke its face through the shelf and look like it is actually rack mounted.”

Finally, Meek recommends a handy labelling tool: “The Brother E550W is a fantastic tool that allows app-based printing. From within the app, you have the facility to print custom stickers to identify the whole consumer unit in one single sticker.”